no longer in general use; fallen into disuse

an obsolete expression.

of a discarded or outmoded type; out of date

an obsolete battleship.

(of a linguistic form) no longer in use, esp., out of use for at least the past century. Compare archaic .

effaced by wearing down or away.

Biology . imperfectly developed or rudimentary in comparison with the corresponding character in other individuals, as of the opposite sex or of a related species.

to make obsolete by replacing with something newer or better; antiquate

Automation has obsoleted many factory workers.

noun

desuetude , disuse , obsoletism