entering vs irruption

entering and irruption both are nouns.

Word	Noun	Adjective	Verb	Adverb
entering	Yes	No	No	No
irruption	Yes	No	No	No

As nouns, irruption is a hyponym of entering; that is, irruption is a word with a more specific, narrower meaning than entering:

entering (noun)	irruption (noun)
the act of entering	a sudden violent entrance; a bursting in
a movement into or inward	a sudden violent spontaneous occurrence (usually of some undesirable condition)
	a sudden sharp increase in the relative numbers of a population