Antonyms for the phrase "stood firm" include words that convey a sense of giving in, yielding, or caving under pressure. Some examples of antonyms for "stood firm" are faltered, wavered, hesitated, surrendered, relented, acquiesced, complied, or succumbed. Essentially, any term that implies a lack of resistance or a weakening of resolve would be considered an antonym for "stood firm." These words might describe a situation where someone was unable to maintain their position, perhaps due to distractions or opposition. By contrast, the phrase "stood firm" suggests a sense of steadfastness, determination, and resoluteness in the face of challenges or adversity.