Call your leader fake (6)
I believe the answer is:
phoney
'fake' is the definition.
(I know that fake can be written as phoney)
'call your leader' is the wordplay.
'call' becomes 'phone' (phone can mean to call by telephone).
'leader' says to take the initial letters.
The first letter of 'your' is 'y'.
'phone'+'y'='PHONEY'
(Other definitions for phoney that I've seen before include "Bogus" , "Sham or insincere" , "Not genuine, insincere" , "Fraud" , "Fake, misleading" .)