enter vs pop in

enter and pop in both are verbs.

Word	Noun	Adjective	Verb	Adverb
enter	No	No	Yes	No
pop in	No	No	Yes	No

As verbs, pop in is a hyponym of enter; that is, pop in is a word with a more specific, narrower meaning than enter:

enter (verb)	pop in (verb)
set out on (an enterprise or subject of study)	enter briefly
make a record of; set down in permanent form
become a participant; be involved in
put or introduce into something
come on stage
to come or go into
take on duties or office
register formally as a participant or member
be or play a part of or in