KanjiJLPT N3
Accidentally

accidentally, even number, couple, man & wife, same kind

Mnemonic

Butler Alfred was polishing silverware when a monkey swung through the window. Alfred accidentally flung a spoon, hitting the monkey on the nose. The startled monkey crashed into a shelf of porcelain dolls. Alfred and the monkey now stand frozen like a pair of idols.
Additional thoughts
Picture Alfred mid-polish, a wild monkey bursting in—their collision is pure coincidence. The porcelain dolls echo the idol/puppet meaning of 偶, and the two standing together reinforces its sense of pair or couple. The chaos is entirely unplanned.
Quick recall
Butler Alfred and a monkey Accidentally collide, ending up frozen together like a pair of idols.

Details

The keyword for 偶 is accidentally. This kanji conveys the idea of something happening by chance, without prior planning or intention. It carries the sense of coincidence or unexpectedness, as when two things come together in an unplanned way. By extension, it can also refer to a pair or couple, reflecting the notion of two things meeting or matching up, as well as to an idol or puppet figure.
On'yomi
ぐう
Kun'yomi
たま