ultracolossal /ˌʌltɹəkəˈlɒsəl/ adjective1 •(rare) Exceedingly colossal; of utmost colossalness.She wasn't going to sit there and watch "ultracolossal nerve" in action, even though she'd consciously chosen to run the risk of her life. — 1995 formsmore ultracolossal · most ultracolossal