drain vs weaken

drain is a noun but weaken is not a noun.

Word	Noun	Adjective	Verb	Adverb
drain	Yes	No	Yes	No
weaken	No	No	Yes	No

As verbs, weaken is a hypernym of drain; that is, weaken is a word with a broader meaning than drain:

drain (noun)	weaken (noun)
emptying something accomplished by allowing liquid to run out of it
a gradual depletion of energy or resources
a pipe through which liquid is carried away
tube inserted into a body cavity (as during surgery) to remove unwanted material

drain (verb)	weaken (verb)
empty of liquid; drain the liquid from	become weaker
make weak	lessen the strength of
deplete of resources	reduce the level or intensity or size or scope of
flow off gradually	lessen in force or effect
	destroy property or hinder normal operations