accident vs chance event

accident and chance event both are nouns.

Word	Noun	Adjective	Verb	Adverb
accident	Yes	No	No	No
chance event	Yes	No	No	No

As nouns, accident and chance event are synonyms defined as:

accident and chance event: anything that happens suddenly or by chance without an apparent cause

Other synonyms of accident include fortuity, stroke.

accident (noun)	chance event (noun)
anything that happens suddenly or by chance without an apparent cause	anything that happens suddenly or by chance without an apparent cause
an unfortunate mishap; especially one causing damage or injury