plunge vs engulf

plunge is a noun but engulf is not a noun.

Word	Noun	Adjective	Verb	Adverb
plunge	Yes	No	Yes	No
engulf	No	No	Yes	No

As verbs, plunge and engulf are synonyms defined as:

Other synonyms of plunge include absorb, engross, immerse, soak up, steep.

plunge (noun)	engulf (noun)
a brief swim in water
a steep and rapid fall

plunge (verb)	engulf (verb)
begin with vigor	devote (oneself) fully to
devote (oneself) fully to	flow over or cover completely
cause to be immersed
immerse briefly into a liquid so as to wet, coat, or saturate
thrust or throw into
fall abruptly
drop steeply
dash violently or with great speed or impetuosity