ACCIDENTAL

I. adjective Date: 14th century arising from extrinsic causes ; incidental , nonessential , 2. occurring unexpectedly or by chance, happening without intent or through carelessness and often with unfortunate results, ~ly also accidently adverb ~ness noun Synonyms: see: ~ II. noun Date: 1651 a nonessential property, 2. a note foreign to a key indicated by a signature, a prefixed sign indicating an ~