Soften; give way (6)
I believe the answer is:
relent
I believe this clue is a double definition.
'soften' is the first definition.
(synonyms)
'give way' is the second definition.
(thesaurus)
(Other definitions for relent that I've seen before include "Change one's mind" , "Be merciful" , "Soften, grow less severe" , "Moderate" , "Ease off" .)