windup vs closing

windup and closing both are nouns.

Word	Noun	Adjective	Verb	Adverb
windup	Yes	Yes	No	No
closing	Yes	Yes	No	No

As nouns, windup and closing are synonyms defined as:

Other synonyms of windup include completion, culmination, mop up.

windup (noun)	closing (noun)
a concluding action	termination of operations
	the act of closing something
	a concluding action
	approaching a particular destination; a coming closer; a narrowing of a gap
	the last section of a communication

windup (adjective)	closing (adjective)
operated by a mechanism	final or ending