slow down vs relax

slow down and relax both are verbs.

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

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

Other synonyms of slow down include decompress, loosen up, unbend, unwind.

slow down (verb)	relax (verb)
become less tense, rest, or take one's ease	become less tense, rest, or take one's ease
lose velocity; move more slowly	cause to feel relaxed
become slow or slower	make less taut
reduce the speed of	become loose or looser or less tight
cause to proceed more slowly	make less active or fast
	become less severe or strict
	make less severe or strict
	become less tense, less formal, or less restrained, and assume a friendlier manner