catch on vs get it

catch on and get it both are verbs.

Word	Noun	Adjective	Verb	Adverb
catch on	No	No	Yes	No
get it	No	No	Yes	No

As verbs, catch on and get it are synonyms defined as:

Other synonyms of catch on include cotton on, get onto, get wise, latch on, tumble, twig.

catch on (verb)	get it (verb)
become popular	understand, usually after some initial difficulty
understand, usually after some initial difficulty	receive punishment; be scolded or reprimanded