He immediately retracted the previous accusation after realizing his mistake.

retracted 是动词 retract 的过去式。retract 由前缀 re-（表示"回、向后"）和词根 tract（表示"拉、拖"）组成，字面意思是"拉回"，引申为"撤回、收回"的意思。在这里指"撤回（之前的言论或指控）"。