The antonyms for the phrase "stay staunch" include words like waver, falter, vacillate, fluctuate, and betray. These words imply an uncertain and unsteady nature, which goes against the steadfastness and loyalty implied by "stay staunch." If one strays from their convictions and beliefs, they may be accused of being fickle, indecisive, or unreliable. Therefore, it is important to remain devoted to one's values and principles, even in the face of adversity. In doing so, we can maintain our integrity and earn the trust and respect of those around us.