part vs split up

part and split up both are nouns.

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

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

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

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

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

part (noun)	split up (noun)
the actions and activities assigned to or required or expected of a person or group	an increase in the number of outstanding shares of a corporation without changing the shareholders' equity
the effort contributed by a person in bringing about a result
something less than the whole of a human artifact
an item that is an instance of some type
a line of scalp that can be seen when sections of hair are combed in opposite directions
one of the portions into which something is regarded as divided and which together constitute a whole
an actor's portrayal of someone in a play
that which concerns a person with regard to a particular role or situation
the melody carried by a particular voice or instrument in polyphonic music
the extended spatial location of something
a portion of a natural object
assets belonging to or due to or contributed by an individual person or group
something determined in relation to something that includes it

part (verb)	split up (verb)
move or break apart	become separated into pieces or fragments
force, take, or pull apart	get a divorce; formally terminate a marriage
depart for someplace	discontinue an association or relation; go different ways
go one's own way; move apart	separate into parts or portions
discontinue an association or relation; go different ways

part (adverb)	split up (adverb)
to some extent; in some degree; not wholly