decrepit vs weakly

decrepit and weakly both are adjectives.

Word	Noun	Adjective	Verb	Adverb
decrepit	No	Yes	No	No
weakly	No	Yes	No	Yes

As adjectives, decrepit and weakly are synonyms defined as:

Other synonyms of decrepit include debile, feeble, infirm, rickety, sapless, weak.

decrepit (adjective)	weakly (adjective)
lacking bodily or muscular strength or vitality	lacking bodily or muscular strength or vitality
worn and broken down by hard use

decrepit (adverb)	weakly (adverb)
	in a weak or feeble manner or to a minor degree