探

The core sense is a tactile search—probing or groping for something hidden, deep, or obscured from view. This includes:

1. Physical probing: Reaching into a space where sight is obstructed (e.g., water, a pit, a crevice).

2. Investigation/Exploration: Intellectual inquiry into the depths of a matter, philosophy, or motive.

3. Technical/Medical: The physical probing of wounds or diagnostic feeling.

Primarily functions as a transitive verb: 探 [object].

Compared to other "searching" terms:

• 尋 (xún): General seeking; looking for something lost or missing.
• 索 (suǒ): A more systematic, demanding, or rigorous search.
• 究 (jiū): An exhaustive investigation intended to reach the absolute bottom or root of a matter.

探 is specifically a "probe," making it more tactile and active than 尋, but less exhaustive than 究.

The glyph emphasizes the act of searching—the reaching and the feeling—rather than the eventual discovery. Additionally, there is usually an implication of depth or concealment; the search is directed toward something that cannot be seen immediately.