One side has the word, one side has the definition. Microwave and dishwasher safe. Lotsa space for your liquids. Buy the mug. 2. heads - up unknown. 1. advance. This Internet Slang page is designed to explain what the meaning of HEADS UP is. The slang word / acronym / abbreviation HEADS UP means . Internet Slang. Define head up (phrasal verb) and get synonyms. What is head up (phrasal verb)? head up (phrasal verb) meaning, pronunciation and more by Macmillan. Hey uruguay football league, heads up! These words appear in red, and are graded with stars. Also called magnetic head. Verbal phrase head up "supervise, direct" is attested by She took it into her head to study medicine. A term in many competitive games for 1 on 1 competition.