The phrase "a go-go" is an informal slang term used to describe something that is abundant or in abundance. It is often used to convey a sense of excitement, liveliness, or excess. The antonyms for "a go-go" are words that convey the opposite meaning. These could include terms such as scarcity, austerity, moderation, restraint, or somberness. These words suggest a more subdued or measured approach to life, rather than one that is characterized by excess or extravagance. While "a go-go" can be fun and exciting in the short term, a more balanced and moderate approach is often necessary for long-term happiness and well-being.