get onto vs get it

get onto and get it both are verbs.

Word	Noun	Adjective	Verb	Adverb
get onto	No	No	Yes	No
get it	No	No	Yes	No

As verbs, get onto and get it are synonyms defined as:

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

get onto (verb)	get it (verb)
understand, usually after some initial difficulty	understand, usually after some initial difficulty
	receive punishment; be scolded or reprimanded