Be patient on account of animal (7)
I believe the answer is:
'be patient' is the definition.
(I've seen this before)
'account of animal' is the wordplay.
'account of' becomes 'for' (I've seen this in other clues).
'animal' becomes 'bear' (bear is a kind of animal).
'on' is the link.
(Other definitions for forbear that I've seen before include "Be patient" , "Refrain from doing something" , "Abstain" , "Hold back" .)