(1):

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

(2):

(a.) No longer in use; gone into disuse; disused; neglected; as, an obsolete word; an obsolete statute; - applied chiefly to words, writings, or observances.

(3):

(v. i.) To become obsolete; to go out of use.