Holiday help! (6)
I believe the answer is:
mayday
I believe this is a double definition.
'holiday' is the first definition.
(I've seen this before)
'help' is the second definition.
(I've seen this before)
(Other definitions for mayday that I've seen before include "When the workers celebrate" , "please help" , "call for help?" , "I'm in trouble" , "International radio distress signal" .)