catch on vs get onto

catch on and get onto both are verbs.

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

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

catch on and get onto: understand, usually after some initial difficulty

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

catch on (verb)	get onto (verb)
become popular	understand, usually after some initial difficulty
understand, usually after some initial difficulty