infirm vs decrepit

infirm and decrepit both are adjectives.

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

As adjectives, infirm and decrepit are synonyms defined as:

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

infirm (adjective)	decrepit (adjective)
lacking bodily or muscular strength or vitality	lacking bodily or muscular strength or vitality
lacking firmness of will or character or purpose	worn and broken down by hard use