slow down vs slow

slow down is not an adjective while slow is an adjective.

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

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

Other synonyms of slow down include decelerate, retard, slow up.

As verbs, slow is a hyponym of slow down; that is, slow is a word with a more specific, narrower meaning than slow down:

Other hyponyms of slow down include slow down, slow up, delay, detain, hold up.

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

Other synonyms of slow down include slack, slacken, slow up.

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

Other synonyms of slow down include slow up.

As verbs, slow is a hypernym of slow down; that is, slow is a word with a broader meaning than slow down:

Other hypernyms of slow down include decelerate, retard, slow down, slow up.

slow down (adjective)	slow (adjective)
	not moving quickly; taking a comparatively long time
	at a slow tempo
	(used of timepieces) indicating a time earlier than the correct time
	(of business) not active or brisk
	slow to learn or understand; lacking intellectual acuity
	so lacking in interest as to cause mental weariness

slow down (verb)	slow (verb)
become less tense, rest, or take one's ease	lose velocity; move more slowly
lose velocity; move more slowly	become slow or slower
become slow or slower	cause to proceed more slowly
reduce the speed of
cause to proceed more slowly

slow down (adverb)	slow (adverb)
	without speed (`slow' is sometimes used informally for `slowly')
	showing a time that is earlier than the actual time