The phrase "hubba hubba" is an informal expression used to express appreciation for someone's physical appearance. Antonyms for this phrase would be words or expressions that convey the opposite sentiment, such as "ugly", "unattractive", "unappealing", or "ordinary". Alternatively, phrases that imply a lack of interest in physical appearance, such as "beauty is only skin deep", "looks aren't everything", or "it's what's on the inside that counts", could also be considered antonyms. While "hubba hubba" may be used as a form of compliment, it is important to remember that appearance is not the only factor that defines a person's worth or beauty.