The Collaborative International Dictionary of English v.0.48:

Less \Less\, v. t.
   To make less; to lessen. [Obs.] --Gower.
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The Collaborative International Dictionary of English v.0.48:

Less \Less\ (l[e^]s), conj.
   Unless. [Obs.] --B. Jonson.
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The Collaborative International Dictionary of English v.0.48:

Less \Less\, a. [OE. lesse, AS. l[=ae]ssa; akin to OFries.
   l[=e]ssa; a compar. from a lost positive form. Cf. Lesser,
   Lest, Least. Less has the sense of the comparative degree
   of little.]
   Smaller; not so large or great; not so much; shorter;
   inferior; as, a less quantity or number; a horse of less size
   or value; in less time than before.
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   Note: The substantive which less qualifies is often omitted;
         as, the purse contained less (money) than ten dollars.
         See Less, n.
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               Thus in less [time] than a hundred years from the
               coming of Augustine, all England became
               Christian.                         --E. A.
                                                  Freeman.
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The Collaborative International Dictionary of English v.0.48:

Less \Less\, adv. [AS. l[=ae]s. See Less, adj., and cf.
   Lest.]
   Not so much; in a smaller or lower degree; as, less bright or
   loud; less beautiful.
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The Collaborative International Dictionary of English v.0.48:

Less \Less\, n.
   1. A smaller portion or quantity.
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            The children of Israel did so, and gathered, some
            more, some less.                      --Ex. xvi. 17.
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   2. The inferior, younger, or smaller.
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            The less is blessed of the better.    --Heb. vii. 7.
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The Collaborative International Dictionary of English v.0.48:

-less \-less\ (-l[e^]s) suff. [AS. le['a]s loose, false; akin to
   OS. l[=o]s loose, false, D. los loose, loos false, sly, G.
   los loose, Icel. lauss loose, vacant, Goth. laus empty, vain,
   and also to E. loose, lose. [root]127. See Lose, and cf.
   Loose, Leasing.]
   A privative adjective suffix, denoting without, destitute of,
   not having; as witless, childless, fatherless.
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WordNet (r) 3.0 (2006):

less
    adv 1: used to form the comparative of some adjectives and
           adverbs; "less interesting"; "less expensive"; "less
           quickly" [syn: less, to a lesser extent] [ant:
           more, to a greater extent]
    2: comparative of little; "she walks less than she should"; "he
       works less these days" [ant: more]
    adj 1: (comparative of `little' usually used with mass nouns) a
           quantifier meaning not as great in amount or degree; "of
           less importance"; "less time to spend with the family";
           "a shower uses less water"; "less than three years old"
           [ant: more than, more(a)]
    2: (usually preceded by `no') lower in quality; "no less than
       perfect"
    3: (nonstandard in some uses but often idiomatic with measure
       phrases) fewer; "less than three weeks"; "no less than 50
       people attended"; "in 25 words or less"

Moby Thesaurus II by Grady Ward, 1.0:

89 Moby Thesaurus words for "less":
   abated, ablated, at a disadvantage, at the nadir, attenuated,
   barring, bated, belittled, below, below the mark, common, consumed,
   contracted, curtailed, decreased, decreasingly, decrescendo,
   deflated, demeaning, diminished, diminishingly, diminuendo,
   disadvantaged, discounting, dissipated, dropped, eroded, ever less,
   except, excepting, exception taken of, excluding, exclusive of,
   fallen, fewer, from, humble, in the gutter, in the shade, inferior,
   infra dig, junior, least, least of all, leaving out, less and less,
   lesser, low, lower, lowered, lowly, miniaturized, minor, minus,
   modest, not counting, not so much, off, ordinary, reduced,
   retrenched, sans, save, scaled-down, second rank, second string,
   secondary, servile, shorn, short of, shorter, shrunk, shrunken,
   smaller, sub, subaltern, subject, subordinate, subservient,
   third rank, third string, under, under par, underprivileged,
   vulgar, watered-down, weakened, without, worn