—n. 1. anything that serves to guide or direct in the solution of a problem, mystery, etc.
2. clew (defs. 1–4, 6, 7).
—v.t. 1. to direct or point out by a clue.
2. clew (def. 8).
3. clue in, a. to provide with useful or reliable information: Clue us in on how these forms are to be filled out. b. to make familiar or aware: Has she been clued in about the rules of this office?