The Collaborative International Dictionary of English v.0.48:

Inclination \In`cli*na"tion\, n. [L. inclinatio: cf. F.
   inclination.]
   [1913 Webster]
   1. The act of inclining, or state of being inclined; a
      leaning; as, an inclination of the head.
      [1913 Webster]

   2. A direction or tendency from the true vertical or
      horizontal direction; as, the inclination of a column, or
      of a road bed.
      [1913 Webster]

   3. A tendency towards another body or point.
      [1913 Webster]

   4. (Geom.) The angle made by two lines or planes; as, the
      inclination of the plane of the earth's equator to the
      plane of the ecliptic is about 23[deg] 28'; the
      inclination of two rays of light.
      [1913 Webster]

   5. A leaning or tendency of the mind, feelings, preferences,
      or will; propensity; a disposition more favorable to one
      thing than to another; favor; desire; love.
      [1913 Webster]

            A mere inclination to a thing is not properly a
            willing of that thing.                --South.
      [1913 Webster]

            How dost thou find the inclination of the people?
                                                  --Shak.
      [1913 Webster]

   6. A person or thing loved or admired. --Sir W. Temple.
      [1913 Webster]

   7. (Pharm.) Decantation, or tipping for pouring.
      [1913 Webster]

   Inclination compass, an inclinometer.

   Inclination of an orbit (Astron.), the angle which the
      orbit makes with the ecliptic.

   Inclination of the needle. See Dip of the needle, under
      Dip.

   Syn: Bent; tendency; proneness; bias; proclivity; propensity;
        prepossession; predilection; attachment; desire;
        affection; love. See Bent, and cf. Disposition.
        [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Dip \Dip\, n.
   1. The action of dipping or plunging for a moment into a
      liquid. "The dip of oars in unison." --Glover.
      [1913 Webster]

   2. Inclination downward; direction below a horizontal line;
      slope; pitch.
      [1913 Webster]

   3. a hollow or depression in a surface, especially in the
      ground.
      [PJC]

   4. A liquid, as a sauce or gravy, served at table with a
      ladle or spoon. [Local, U.S.] --Bartlett.
      [1913 Webster]

   5. A dipped candle. [Colloq.] --Marryat.
      [1913 Webster]

   6. A gymnastic exercise on the parallel bars in which the
      performer, resting on his hands, lets his arms bend and
      his body sink until his chin is level with the bars, and
      then raises himself by straightening his arms.
      [Webster 1913 Suppl.]

   7. In the turpentine industry, the viscid exudation, which is
      dipped out from incisions in the trees; as, virgin dip
      (the runnings of the first year), yellow dip (the runnings
      of subsequent years).
      [Webster 1913 Suppl.]

   8. (A["e]ronautics) A sudden drop followed by a climb,
      usually to avoid obstacles or as the result of getting
      into an airhole.
      [Webster 1913 Suppl.]

   9. a liquid, in which objects are soaked by dipping; e.g., a
      parasiticide or insecticide solution into which animals
      are dipped (see sheep-dip).
      [PJC]

   10. a sauce into which foods are dipped to enhance the
       flavor; e. g., an onion dip made from sour cream and
       dried onions, into which potato chips are dipped.
       [PJC]

   11. a pickpocket. [slang]
       [PJC]

   Dip of the horizon (Astron.), the angular depression of the
      seen or visible horizon below the true or natural horizon;
      the angle at the eye of an observer between a horizontal
      line and a tangent drawn from the eye to the surface of
      the ocean.

   Dip of the needle, or Magnetic dip, the angle formed, in
      a vertical plane, by a freely suspended magnetic needle,
      or the line of magnetic force, with a horizontal line; --
      called also inclination.

   Dip of a stratum (Geol.), its greatest angle of inclination
      to the horizon, or that of a line perpendicular to its
      direction or strike; -- called also the pitch.
      [1913 Webster]

WordNet (r) 3.0 (2006):

inclination
    n 1: an attitude of mind especially one that favors one
         alternative over others; "he had an inclination to give up
         too easily"; "a tendency to be too strict" [syn:
         inclination, disposition, tendency]
    2: (astronomy) the angle between the plane of the orbit and the
       plane of the ecliptic stated in degrees [syn: inclination,
       inclination of an orbit]
    3: (geometry) the angle formed by the x-axis and a given line
       (measured counterclockwise from the positive half of the
       x-axis) [syn: inclination, angle of inclination]
    4: (physics) the angle that a magnetic needle makes with the
       plane of the horizon [syn: dip, angle of dip, magnetic
       dip, magnetic inclination, inclination]
    5: that toward which you are inclined to feel a liking; "her
       inclination is for classical music" [ant: disinclination]
    6: the property possessed by a line or surface that departs from
       the vertical; "the tower had a pronounced tilt"; "the ship
       developed a list to starboard"; "he walked with a heavy
       inclination to the right" [syn: tilt, list,
       inclination, lean, leaning]
    7: a characteristic likelihood of or natural disposition toward
       a certain condition or character or effect; "the alkaline
       inclination of the local waters"; "fabric with a tendency to
       shrink" [syn: tendency, inclination]
    8: the act of inclining; bending forward; "an inclination of his
       head indicated his agreement" [syn: inclination,
       inclining]

Moby Thesaurus II by Grady Ward, 1.0:

273 Moby Thesaurus words for "inclination":
   a thing for, affection, affinity, aim, an ear for, an eye for,
   angle, angularity, animus, appetence, appetency, appetite,
   aptitude, aptness, ardor, attitude, azimuth, bag, bank, bearing,
   bend, bending, bending the knee, bent, bevel, bezel, bias, bob,
   bow, bowing, bowing and scraping, cant, capacity for, cascade,
   cast, cataract, character, choice, chosen kind, chute, collapse,
   comedown, command, conation, conatus, conduciveness, constitution,
   course, crash, craving, cup of tea, current, curtsy, debacle,
   decision, declension, declination, defluxion, delight, descending,
   descension, descent, desire, determination, diathesis,
   dipping the colors, direction, direction line, discretion,
   discrimination, disposition, down, downbend, downcome, downcurve,
   downfall, downflow, downgrade, downpour, downrush, downtrend,
   downturn, downward trend, drift, drop, dropping, druthers,
   eagerness, easy slope, eccentricity, enthusiasm, fall, falling,
   fancy, fascination, favor, favoritism, feeling for, felicity,
   fervor, flair, fleam, forejudgment, free choice, free will,
   genius for, gentle slope, genuflection, gift for, glacis, grade,
   gradient, grain, gravitation, hanging gardens, heading, helicline,
   helmsmanship, hillside, homage, idiosyncrasy, incline,
   inclined plane, inclining, individualism, inequality,
   innate aptitude, intention, interest, involvement, jaundice,
   jaundiced eye, kidney, kneeling, kowtow, launching ramp, lay, lean,
   leaning, leaning tower, liability, lie, liking, line,
   line of direction, line of march, list, longing, lust, make,
   makeup, making a leg, mental set, mettle, mind, mind-set, mold,
   mutual affinity, mutual attraction, nature, navigation, nepotism,
   nod, nodding, obeisance, objective, obsequiousness, one-sidedness,
   orientation, parti pris, partialism, partiality, particular choice,
   partisanism, partisanship, passion, penchant, personal choice,
   piloting, pitch, pleasure, plummeting, point, pounce,
   preconception, predilection, predisposition, preference,
   preferential treatment, prejudgment, prejudice, prepossession,
   presenting arms, probability, proclivity, proneness, propensity,
   prostration, quarter, rake, ramp, range, rapids, readiness,
   resolution, reverence, run, salaam, salutation, salute, scarp,
   scrape, sensitivity to, servility, set, sexual desire,
   shelving beach, side, slant, slope, soft spot, stamp,
   standing at attention, steep slope, steerage, steering,
   stiff climb, stomach, stoop, strain, streak, stripe, style,
   submission, submissiveness, susceptibility, swag, sway, swoop,
   sympathy, talus, taste, temper, temperament, tendency, tenor,
   thing, tilt, tilting, tip, tower of Pisa, track, trend, tropism,
   turn, turn for, turn of mind, twist, type, undetachment,
   undispassionateness, unneutrality, velleity, volition, warp,
   waterfall, way, weakness, will, will power, willingness, wish,
   zeal