occurrent vs happening

occurrent and happening both are nouns.

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

As nouns, occurrent and happening are synonyms defined as:

Other synonyms of occurrent include natural event, occurrence.

occurrent (noun)	happening (noun)
an event that happens	an event that happens

occurrent (adjective)	happening (adjective)
presently occurring (either causally or incidentally)