Who may give injured camper aid? (9)
I believe the answer is:
paramedic
'who may' is the definition.
Although both the answer and definition are singular nouns, I don't see how they can define each other.
'injured camper aid?' is the wordplay.
'injured' indicates an anagram.
'camper'+'aid'='camperaid'
'camperaid' is an anagram of 'PARAMEDIC'.
'give' is the link.
(Other definitions for paramedic that I've seen before include "Professional first-aider" , "Emergency first-aider" , "Assistant in ambulance maybe" , "first aider" , "Emergency worker" .)