Synonyms of the word 
UNEXPECTEDLY → ACCIDENTALLY - CIRCUMSTANTIALLY
unexpectedly
- adv. In an unexpected manner.
accidentally
- adv. In an accidental manner; unexpectedly; by chance; casually; fortuitously.
- adv. Unintentionally.
circumstantially
- adv. in a circumstantial manner.
- adv. In respect to circumstances; not essentially; accidentally.
- adv. In every circumstance or particular; minutely.
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