adverb
unusually; contrary to one's habit
Used when someone's behavior or a situation deviates from the usual pattern. Often implies a surprising or notable departure from the norm.
彼は例に無く早く帰宅した。
He went home unusually early.
例に無く、今日の会議は長引いた。
Unusually, today's meeting dragged on.
Similar meaning, but いつになく emphasizes a departure from one's usual state at a particular time, while 例に無く focuses on breaking a habitual pattern.
Compound of 例 (rei, 'usual case') + に (ni, particle) + 無く (naku, adverbial form of 無い 'not exist'). Literally 'without precedent in one's usual case'.