Stop holiday, did you say? (5)
I believe the answer is:
brake
'stop' is the definition.
(braking is a kind of stopping)
'holiday did you say?' is the wordplay.
'holiday' becomes 'break' (I've seen this before).
'did you say?' shows a homophone (sound like).
'break' is a homophone of 'BRAKE'.
(Other definitions for brake that I've seen before include "Thicket; fern; slow down" , "Slower" , "Restraint on vehicle" , "Cause to slow down" , "Car stopper or thicket" .)