"Lived it up" is an idiom that means someone had a good and exciting time. The antonyms for "lived it up" would be words or phrases that describe a boring, unhappy, or uneventful experience. Examples include "lived it down," which suggests someone is ashamed or regretful of their actions, "lived a dull life," indicating a lack of excitement or joy, or "lived through a nightmare," which implies a traumatic or unpleasant experience. These antonyms suggest a contrast to the fun and exciting connotations of "lived it up" and imply negative or undesirable experiences.