split vs split up

split and split up both are nouns.

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

As nouns, split and split up are synonyms defined as:

split and split up: an increase in the number of outstanding shares of a corporation without changing the shareholders' equity

Other synonyms of split include stock split.

As verbs, split up is a hypernym of split; that is, split up is a word with a broader meaning than split:

Other hypernyms of split include break, come apart, fall apart, separate.

As verbs, split and split up are synonyms defined as:

split and split up: discontinue an association or relation; go different ways

Other synonyms of split include break, break up, part, separate.

As verbs, split up is a hyponym of split; that is, split up is a word with a more specific, narrower meaning than split:

As verbs, split and split up are synonyms defined as:

Other synonyms of split include carve up, dissever, divide, separate.

split (noun)	split up (noun)
division of a group into opposing factions	an increase in the number of outstanding shares of a corporation without changing the shareholders' equity
the act of rending or ripping or splitting something
extending the legs at right angles to the trunk (one in front and the other in back)
an increase in the number of outstanding shares of a corporation without changing the shareholders' equity
(tenpin bowling) a divided formation of pins left standing after the first bowl
a dessert of sliced fruit and ice cream covered with whipped cream and cherries and nuts
an opening made forcibly as by pulling apart
a lengthwise crack in wood
a promised or claimed share of loot or money
a bottle containing half the usual amount

split (adjective)	split up (adjective)
(especially of wood) cut or ripped longitudinally with the grain
having been divided; having the unity destroyed

split (verb)	split up (verb)
come open suddenly and violently, as if from internal pressure	become separated into pieces or fragments
separate or cut with a tool, such as a sharp instrument	get a divorce; formally terminate a marriage
go one's own way; move apart	discontinue an association or relation; go different ways
discontinue an association or relation; go different ways	separate into parts or portions
separate into parts or portions