break (v)
break up (v)
part (v)
separate (v)
split (v)
split up (v)

Definition: discontinue an association or relation
Example: The business partners broke over a tax question. The couple separated after 25 years of marriage. My friend and I split up.

part (v)
separate (v)
split (v)

Definition: go one's own way
Example: The friends separated after the party.

disunite (v)
divide (v)
part (v)
separate (v)

Definition: force, take, or pull apart
Example: He separated the fighting children. Moses parted the Red Sea.