The antonyms for the phrase "firmed a deal" could include actions such as breaking off negotiations, failing to reach an agreement, or withdrawing an offer. Other opposite actions could be hesitating, succumbing to indecisiveness, lacking commitment, or being unable to finalize a contract. When parties involved in a deal are unable to agree on terms or balk at following through with signed contracts, it can lead to a sense of uncertainty or mistrust between them. In contrast, successfully firmed deals foster positive relationships, trust, and growth between individuals, businesses, or organizations.