30 accidentally synonyms include fortuitously, by accident, by chance, by a mere chance, by a twist of fate, adventitiously, and coincidentally. Accidentally is an adverb, and its antonym is systematically. Here are some additional synonyms for "accidentally" with example sentences.
30 other ways to say accidentally.
He accidentally stepped on the accelerator instead of the brake.
I accidentally spilled coffee on my shirt.
She accidentally hit her elbow on the table.
They left the door open accidentally.