unwind vs slow down

unwind and slow down both are verbs.

Word	Noun	Adjective	Verb	Adverb
unwind	No	No	Yes	No
slow down	No	No	Yes	No

As verbs, unwind and slow down are synonyms defined as:

Other synonyms of unwind include decompress, loosen up, relax, unbend.

unwind (verb)	slow down (verb)
become less tense, rest, or take one's ease	become less tense, rest, or take one's ease
cause to feel relaxed	lose velocity; move more slowly
separate the tangles of	become slow or slower
reverse the winding or twisting of	reduce the speed of
	cause to proceed more slowly