emptying vs drain

emptying and drain both are nouns.

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

As nouns, drain is a hyponym of emptying; that is, drain is a word with a more specific, narrower meaning than emptying:

Other hyponyms of emptying include drainage.

emptying (noun)	drain (noun)
the act of removing the contents of something	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

emptying (verb)	drain (verb)
	empty of liquid; drain the liquid from
	make weak
	deplete of resources
	flow off gradually