The Collaborative International Dictionary of English v.0.48:

Fluent \Flu"ent\, a. [L. fluens, -entis, p. pr. of fluere to
   flow; cf. Gr. ? to boil over. Cf. Fluctuate, Flux.]
   1. Flowing or capable of flowing; liquid; glodding; easily
      moving.
      [1913 Webster]

   2. Ready in the use of words; voluble; copious; having words
      at command; and uttering them with facility and
      smoothness; as, a fluent speaker; hence, flowing; voluble;
      smooth; -- said of language; as, fluent speech.
      [1913 Webster]

            With most fluent utterance.           --Denham.
      [1913 Webster]

            Fluent as the flight of a swallow is the sultan's
            letter.                               --De Quincey.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Fluent \Flu"ent\, n.
   1. A current of water; a stream. [Obs.]
      [1913 Webster]

   2. [Cf. F. fluente.] (Math.) A variable quantity, considered
      as increasing or diminishing; -- called, in the modern
      calculus, the function or integral.
      [1913 Webster]

WordNet (r) 3.0 (2006):

fluent
    adj 1: smooth and unconstrained in movement; "a long, smooth
           stride"; "the fluid motion of a cat"; "the liquid grace
           of a ballerina" [syn: fluent, fluid, liquid,
           smooth]
    2: expressing yourself readily, clearly, effectively; "able to
       dazzle with his facile tongue"; "silver speech" [syn:
       eloquent, facile, fluent, silver, silver-tongued,
       smooth-spoken]

Moby Thesaurus II by Grady Ward, 1.0:

133 Moby Thesaurus words for "fluent":
   affluent, all jaw, apt, articulate, ascending, axial, back,
   back-flowing, backward, balanced, candid, chatty, communicative,
   concinnate, concinnous, confluent, conversational, coursing,
   cursive, decurrent, defluent, descending, diffluent, down-trending,
   downward, drifting, easy, effortless, effusive, elegant, eloquent,
   euphonic, euphonical, euphonious, expansive, expressive, facile,
   felicitous, flip, flowing, fluid, fluidal, fluidic, fluxible,
   fluxile, fluxional, fluxionary, fluxive, flying, frank, gabby,
   garrulous, gassy, glib, going, gossipy, graceful, gregarious,
   gulfy, gushing, gushy, gyrational, gyratory, harmonious, juicy,
   liquid, liquidy, long-winded, loquacious, mazy, meandering,
   measured, mounting, multiloquent, multiloquious, natural, newsy,
   ordered, orderly, overtalkative, passing, pleasing, plunging,
   polished, pouring, profluent, progressive, prolix, prompt, quick,
   racing, ready, reflowing, refluent, regressive, retrogressive,
   rising, rotary, rotational, rotatory, running, runny, rushing,
   sappy, serpentine, sideward, sinking, slick, sluggish, smooth,
   smooth-sounding, smooth-spoken, soaring, sociable, streaming,
   succulent, surging, surgy, sweet, symmetrical, talkative, talky,
   tidal, tripping, up-trending, upward, verbose, vocal, voluble,
   vortical, watery, well-spoken, windy