偵

Phono-semantic compound:

人 (亻, person radical) - semantic: human activity.

貞 (upright, steadfast) - phonetic element providing sound.

Thus, originally “a person engaged in watching or inquiring,” later extended to “spy, investigate.”

Semantic range:

- to spy, to reconnoiter (정탐하다, 염탐하다);

- to investigate, examine (탐사하다);

- by extension: inquiry, detection.

偵察 (정찰) — reconnaissance, scouting

偵探 (정탐) — to spy, detective

偵候 (정후) — scout, advance warning

密偵 (밀정) — secret agent, undercover spy

In military texts (e.g., Sunzi’s Art of War), 偵 is central to strategy, denoting scouts and intelligence gathering.

In modern East Asian languages, it evolved into everyday terms for detectives (탐정 in Korean, 探偵 in Japanese).