The phrase "bug up" does not have an established antonym as it is not a commonly used phrase in English language. However, the word "bug" has multiple meanings and antonyms depending on the context. As a noun, bug can mean an insect or microbe, and the antonym can be a larger organism or a sanitizing agent. As a verb, bug can mean to bother, annoy, or irritate, and the antonyms can be to help, comfort, or soothe. In programming language, a bug refers to an error in the code, and the antonym can be correct or accurate code. In conclusion, bug up does not have an antonym, but the word "bug" has multiple meanings and antonyms depending on the context.