decelerate vs detain

decelerate and detain both are verbs.

Word	Noun	Adjective	Verb	Adverb
decelerate	No	No	Yes	No
detain	No	No	Yes	No

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

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

decelerate (verb)	detain (verb)
lose velocity; move more slowly	cause to be slowed down or delayed
reduce the speed of	stop or halt
	deprive of freedom; take into confinement