Complaint demanding attention by a guerrilla leader (7)
I believe the answer is:
earache
'complaint' is the definition.
(a type of medical complaint)
'attention by a guerrilla leader' is the wordplay.
'attention' becomes 'ear' (having someone's ear is having their attention).
'by' means one lot of letters go next to another.
'guerrilla leader' becomes 'che' (guerrilla revolutionary Che Guevara).
'ear'+'a'+'che'='EARACHE'
'demanding' acts as a link.
(Other definitions for earache that I've seen before include "Form of torture" , "Pain in an aural appendage" , "Pain for listener" , "Ace hare (anag.)" , "complaint to The Listener" .)