noun
stroke of luck; unexpected good fortune; godsend; windfall
Refers to a piece of luck that comes unexpectedly, often with a nuance of undeserved or rare fortune. Somewhat literary or formal; in casual speech, ラッキー or 幸運 is more common.
彼が無事だったのはまさに僥倖だった。
It was truly a stroke of luck that he was unharmed.
この僥倖を無駄にしてはいけない。
We must not waste this godsend.
The word is composed of two kanji, both meaning 'luck' or 'fortune'. The exact historical derivation is uncertain, but it is a Sino-Japanese compound (kango) that has been used in literary Japanese for centuries.