irruption vs happening

irruption and happening both are nouns.

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

As nouns, happening is a hypernym of irruption; that is, happening is a word with a broader meaning than irruption:

irruption: a sudden violent spontaneous occurrence (usually of some undesirable condition)
happening: an event that happens

Other hypernyms of irruption include natural event, occurrence, occurrent.

irruption (noun)	happening (noun)
a sudden violent entrance; a bursting in	an event that happens
a sudden violent spontaneous occurrence (usually of some undesirable condition)
a sudden sharp increase in the relative numbers of a population