Hint: something wielded in the Billiard Room (3)
I believe the answer is:
cue
'hint' is the definition.
(cue can mean a hint or prompt)
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for cue that I've seen before include "A snooker ball striker" , "Billiards stick" , "Tapering stick used by snooker player" , "Signal (to actor)" , "Potter" .)