dive vs nosedive

dive and nosedive both are nouns.

Word	Noun	Adjective	Verb	Adverb
dive	Yes	No	Yes	No
nosedive	Yes	No	Yes	No

As nouns, dive and nosedive are synonyms defined as:

Other synonyms of dive include nose dive.

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

Other hyponyms of dive include power-dive, duck, crash-dive, chute, jump, parachute.

dive (noun)	nosedive (noun)
a steep nose-down descent by an aircraft	a steep nose-down descent by an aircraft
a headlong plunge into water	a sudden sharp drop or rapid decline
a cheap disreputable nightclub or dance hall

dive (verb)	nosedive (verb)
drop steeply	plunge nose first; drop with the nose or front first, of aircraft
swim under water
plunge into water