破綻(はたん)

failure; collapse; breakdown

破綻(はたん)する

to fail; to break down; to collapse

綻(ほころ)び

tear; rip; flaw; unraveling

綻(ほころ)びる

to come undone; to unravel; to begin to open

口元(くちもと)が綻(ほころ)びる

the corners of one's mouth begin to smile

綻(ほころ)び始(はじ)める

begin to unravel

綻(ほころ)びかける

be about to unravel

彼(かれ)の説明(せつめい)を聞(き)くと、口元(くちもと)が綻(ほころ)びる。

When I hear his explanation, a smile appears on my lips.

春(はる)になると、庭(にわ)の蕾(つぼみ)が綻(ほころ)ぶ。

When spring arrives, the garden buds begin to open.