Un-effusive refers to something that is restrained or lacking in enthusiasm. The antonyms of un-effusive include demonstrative, effusive, extravagant, lavish, exuberant, and overly expressive. Demonstrative refers to something that shows feeling or emotion openly and extravagantly. Effusive, on the other hand, means to express one's feelings or gratitude in an overtly emotional manner. Lavish implies a generous, abundant, or unnecessarily wasteful display of emotions or actions. Exuberant means excessively joyful, energetic, or enthusiastic in expressing feelings. Using these antonyms for un-effusive helps to convey different emotions and attitudes in writing or speech, thus making communication more interesting and effective.