Prepare for holiday crowd (4)
I believe the answer is:
pack
I believe this clue is a double definition.
'prepare for holiday' is the first definition.
(eg pack a suitcase)
'crowd' is the second definition.
(I know that pack is a more specific form of crowd)
(Other definitions for pack that I've seen before include "Wolf group" , "Put clothes etc into suitcase" , "Fill luggage - wolves" , "Cards; group of animals" , "Group (of wolves)" .)