相そう好ごうを崩くずすそうごうをくずすConjugationMeanings1expression, godan verb (-su)smile broadly; grin widelyIdiomatic expression describing a sudden, unreserved smile that breaks one's usual composed expression. Often used when someone cannot help but smile.孫まごの顔かおを見みて、祖そ父ふは思おもわず相そう好ごうを崩くずした。Seeing his grandchild's face, the grandfather couldn't help but smile broadly.
