rabbit on vs rant

rabbit on is not a noun while rant is a noun.

Word	Noun	Adjective	Verb	Adverb
rabbit on	No	No	Yes	No
rant	Yes	No	Yes	No

As verbs, rabbit on and rant are synonyms defined as:

Other synonyms of rabbit on include jabber, mouth off, rave, spout.

rabbit on (noun)	rant (noun)
	pompous or pretentious talk or writing
	a loud bombastic declamation expressed with strong emotion

rabbit on (verb)	rant (verb)
talk in a noisy, excited, or declamatory manner	talk in a noisy, excited, or declamatory manner