pop out vs bulge

pop out is not a noun while bulge is a noun.

Word	Noun	Adjective	Verb	Adverb
pop out	No	No	Yes	No
bulge	Yes	No	Yes	No

As verbs, pop out and bulge are synonyms defined as:

Other synonyms of pop out include bug out, bulge out, come out, pop, protrude, start.

pop out (noun)	bulge (noun)
	something that bulges out or is protuberant or projects from its surroundings

pop out (verb)	bulge (verb)
come out suddenly or forcefully	swell or protrude outwards
exit briefly	cause to bulge or swell outwards
bulge outward	bulge outward
appear suddenly or unexpectedly; happen unexpectedly	bulge out; form a bulge outward, or be so full as to appear to bulge