slow down vs fishtail

slow down and fishtail both are verbs.

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

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

Other hyponyms of slow down include moderate, retard.

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