Source : Webster's Revised Unabridged Dictionary (1913)

Obsolete \Ob"so*lete\, a. [L. obsoletus, p. p. of obsolescere.
   See {Obsolescent}.]
   1. No longer in use; gone into disuse; disused; neglected;
      as, an obsolete word; an obsolete statute; -- applied
      chiefly to words, writings, or observances.

   2. (Biol.) Not very distinct; obscure; rudimental;
      imperfectly developed; abortive.

   Syn: Ancient; antiquated; old-fashioned; antique; old;
        disused; neglected. See {Ancient}.

Obsolete \Ob"so*lete\, v. i.
   To become obsolete; to go out of use. [R.] --Fitzed. Hall.

Source : WordNet®

obsolete
     adj 1: old; no longer in use or valid or fashionable; "obsolete
            words"; "an obsolete locomotive"; "outdated
            equipment"; "superannuated laws"; "out-of-date ideas"
            [syn: {outdated}, {out-of-date}, {superannuated}]
     2: no longer in use; "obsolete words" [syn: {disused}]