A holiday that will make you jolly? (4,4)
I believe the answer is:
half term
'a holiday' is the definition.
(I've seen this before)
'jolly?' is the wordplay.
I cannot really understand how this works, but
'jolly?' could be 'rm' and 'rm' is located in the answer.
This explanation may well be incorrect...
'that will make you' acts as a link.
(Other definitions for half term that I've seen before include "Short holiday during school semester" , "Short school vacation" , "Short school break" , "Break during division of school year" , "twenty-weeks pregnant?" .)