first and final offer in labor-management negotiations
A single, take-it-or-leave-it proposal presented by management to a union, typically at the start of negotiations, with no room for further bargaining.
The company presented a first and final offer, stating that no further concessions could be made.
The union strongly opposed the take-it-or-leave-it offer and went on strike.
最終回答 is a final answer or offer, but it may come after some negotiation; 一発回答 is presented from the start as the only offer.
Compound of 一発 (one shot, single action) and 回答 (answer, reply). The term is used in labor relations to describe a single, non-negotiable offer.