The phrase "raps on knuckles" generally refers to a gentle punishment or reprimand for wrongdoing. However, there are several antonyms for this phrase, which include praise, commendation, and commendatory remarks. These words denote words of approval, admiration, and appreciation for someone's achievements or actions. Where raps on knuckles carry a negative connotation, these antonyms carry a positive connotation, and they embody the opposite of a punishment or reprimand. Therefore, depending on the situation, you can choose to employ the appropriate antonym that would suitably reflect the tone and message you want to convey.