Clergyman gets tongue back (7)
I believe the answer is:
reverse
'back' is the definition.
(back can mean to reverse)
'clergyman gets tongue' is the wordplay.
'clergyman' becomes 'rev' (short for reverend).
'gets' is a charade indicator (letters next to each other).
'tongue' becomes 'erse' (Erse is an example).
'rev'+'erse'='REVERSE'
(Other definitions for reverse that I've seen before include "Tails (of a coin)" , "Turn inside out or upside down" , "Transpose" , "Go in the opposite direction" , "contrary" .)