boil vs boil over

boil is a noun but boil over is not a noun.

Word	Noun	Adjective	Verb	Adverb
boil	Yes	No	Yes	No
boil over	No	No	Yes	No

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

Other hyponyms of boil include overboil.

boil (noun)	boil over (noun)
the temperature at which a liquid boils at sea level
a painful sore with a hard core filled with pus

boil (verb)	boil over (verb)
immerse or be immersed in a boiling liquid, often for cooking purposes	overflow or cause to overflow while boiling
come to the boiling point and change from a liquid to vapor
bring to, or maintain at, the boiling point
be in an agitated emotional state
be agitated