detain vs detention

detain is not a noun while detention is a noun.

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

detain (noun)	detention (noun)
	a punishment in which a student must stay at school after others have gone home
	a state of being confined (usually for a short time)

detain (verb)	detention (verb)
cause to be slowed down or delayed
stop or halt
deprive of freedom; take into confinement