split up vs conjoin

split up is a noun but conjoin is not a noun.

Word	Noun	Adjective	Verb	Adverb
split up	Yes	No	Yes	No
conjoin	No	No	Yes	No

split up (noun)	conjoin (noun)
an increase in the number of outstanding shares of a corporation without changing the shareholders' equity

split up (verb)	conjoin (verb)
become separated into pieces or fragments	make contact or come together
get a divorce; formally terminate a marriage	take in marriage; married
discontinue an association or relation; go different ways
separate into parts or portions