KanjiJLPT N2
Inquire

inquire, fathom, look for

Mnemonic

A comb is lodged deep in the carpenter's workbench. You open your mouth to inquire whose it is. The carpenter grabs a measurement tape, stretches both arms wide, and declares, 'It belongs to whoever matches this measurement—one full arm-span!'
Additional thoughts
The outstretched arms recall the classical meaning of 尋 as a unit of length (~6 feet). Picture the carpenter holding the comb in one hand, tape in the other, mouth open wide, interrogating everyone in the shop.
Quick recall
A comb stuck in a carpenter's bench makes you open your mouth to inquire, while a measurement tape stretches arm-span wide.

Details

The keyword for 尋 is inquire. This kanji conveys the act of asking, searching for, or seeking out information by questioning others. It carries the sense of actively pursuing knowledge or tracking something down through investigation. In classical usage, it also referred to a traditional unit of length (approximately six feet), measured by the span of outstretched arms, though its primary modern usage centers on the idea of questioning and seeking.
On'yomi
じん
Kun'yomi
たず.ねる、ひろ