Learnt to become forbearing (8)
I believe the answer is:
tolerant
'forbearing' is the definition.
(synonyms)
'learnt to become' is the wordplay.
'become' indicates anagramming the letters.
'learnt'+'to'='learntto'
'learntto' anagrammed gives 'TOLERANT'.
(Other definitions for tolerant that I've seen before include "Learnt to be at home with others' beliefs" , "Showing respect for the opinions of others" , "Liberal" , "Broadminded, acceptance of others' beliefs" , "Allowing carte blanche" .)