An object or a kind of indication which may be used as evidence.
Information which may lead one to a certain point or conclusion.
Insight or understanding ("to have a clue [about]" or "to have clue". See have a clue, clue stick)
To provide with a clue.
To provide someone with information which he or she lacks (often used with "in" or "up").
An indication that someone or something is in danger or at risk
A sign that indicates a danger, for example to vehicles on a road or of hazardous chemicals.