Denshi Jisho — Online Japanese dictionary

綻び ほころび open seam; seam that has come apart; tear
Noun 
綻ぶ ほころぶ 1: to begin to open; to come out;
2: to smile broadly;
3: to come apart at the seams (clothes)
Godan verb with bu ending 
綻びる ほころびる 1: to come apart at the seams; to be ripped; to be torn;
2: to begin to open; to begin to bloom;
3: to smile broadly; to break into a smile
Common word, Ichidan verb, Intransitive verb 

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