halt vs standstill

halt and standstill both are nouns.

Word	Noun	Adjective	Verb	Adverb
halt	Yes	Yes	Yes	No
standstill	Yes	No	No	No

As nouns, standstill is a hyponym of halt; that is, standstill is a word with a more specific, narrower meaning than halt:

Other hyponyms of halt include cessation, surcease, stand, tie-up.

halt (noun)	standstill (noun)
an interruption or temporary suspension of progress or movement	an interruption of normal activity
the event of something ending	a situation in which no progress can be made or no advancement is possible
the state of inactivity following an interruption

halt (adjective)	standstill (adjective)
disabled in the feet or legs

halt (verb)	standstill (verb)
stop the flow of a liquid
come to a halt, stop moving
cause to come to an abrupt stop
stop from happening or developing