The antonyms for the word "un-extravagant" include words such as lavish, excessive, over-the-top, wasteful, and flamboyant. These terms are commonly used to describe individuals or events that are characterized by an abundance of luxury or indulgence. Antonyms for "un-extravagant" can also include terms like frugal, thrifty, economical, and modest, which are used to denote people or occasions that are characterized by simplicity or restraint. When choosing between extravagant or un-extravagant, it is important to consider the context of the situation and the impression that you wish to convey.