Depart, for holiday, say (5)
I believe the answer is:
leave
I believe this clue is a triple definition!
'depart' is the first definition.
(I know that depart is a more specific form of leave)
'for holiday' is the second definition.
(I've seen this before)
'say' is the third definition.
(I know that say is a more specific form of convey)
(Other definitions for leave that I've seen before include "Exit" , "Depart on work holiday?" , "Permission (to take holidays?)" , "Go away on holiday" , "Permission to go; allow to remain" .)