プログレッシブ和英中辞典(第4版)の解説
ふりこう【不履行】
nonfulfillment；《英》 nonfulfilment
約束の不履行
failure to keep a promise／(a) breach of promise
今日会議に欠席すれば義務の不履行になる
It would be a breach of duty if I didn't attend the meeting today.
契約の不履行
(a) breach of contract／nonfulfillment of a contract
債務の不履行
default (on a payment)／failure to pay [make payment]
契約不履行のため違約金を取られた
I had to pay a penalty for not fulfilling the terms of the contract.