Letted go is an expression that means releasing or relinquishing something, usually a person or an object. There are several antonyms for this phrase. The first antonym is clench, which means to grip or hold tightly. Another antonym is grasp, which means to take hold of something firmly. On the other hand, retain is an antonym that means to keep or hold onto something. The final antonym is immobilize, which means to make something still or fixed. These antonyms convey the opposite meaning of letted go and demonstrate various ways of controlling or holding onto something.