Give aid to guitar player having missed intro (6)
I believe the answer is:
assist
'give aid' is the definition.
(I've seen this before)
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for assist that I've seen before include "provide backing" , "Give help" , "Pitch in" , "Pass to scorer" , "Work with N help" .)