superannuated vs over-the-hill

superannuated and over-the-hill both are adjectives.

Word	Noun	Adjective	Verb	Adverb
superannuated	No	Yes	No	No
over-the-hill	No	Yes	No	No

As adjectives, superannuated and over-the-hill are synonyms defined as:

Other synonyms of superannuated include overage, overaged.

superannuated (adjective)	over-the-hill (adjective)
old; no longer valid or fashionable	too old to be useful
too old to be useful