The phrase "knocked props out" can refer to something being undermined or weakened. The antonyms for this phrase would be to bolster, strengthen, or support. Instead of knocking the props out, people could provide additional reinforcement, backing, or validation to build up and fortify a system or structure. Additionally, the phrase could imply someone being emotionally or mentally defeated, and antonyms in this case would be to encourage, motivate, or uplift. Providing positive feedback, inspiration, or praise could help someone regain confidence and overcome obstacles. Ultimately, instead of tearing something down or causing harm, antonyms for "knocked props out" focus on elevating and empowering.