Beggar working in tandem with head of charity (9)
I believe the answer is:
mendicant
'beggar' is the definition.
('mendicant' can be a synonym of 'beggar')
'working in tandem with head of charity' is the wordplay.
'working' indicates anagramming the letters.
'with' indicates putting letters inside.
'head of' says to take the initial letters.
The first letter of 'charity' is 'c'.
'in'+'tandem'='intandem'
'intandem' with letters rearranged gives 'mendiant'.
'mendiant' going around 'c' is 'MENDICANT'.
(Other definitions for mendicant that I've seen before include "Beggar" , "Begging" .)