divide vs break off

divide is a noun but break off is not a noun.

Word	Noun	Adjective	Verb	Adverb
divide	Yes	No	Yes	No
break off	No	No	Yes	No

As verbs, break off is a hyponym of divide; that is, break off is a word with a more specific, narrower meaning than divide:

divide (noun)	break off (noun)
a ridge of land that separates two adjacent river systems
a serious disagreement between two groups of people (typically producing tension or hostility)

divide (verb)	break off (verb)
perform a division	prevent completion
move or break apart	interrupt before its natural or planned end
force, take, or pull apart	break a small piece off from
make a division or separation	break off (a piece from a whole)
separate into parts or portions	break a piece from a whole
act as a barrier between; stand between