The opposite or antonym for the word 'un-movable' is 'movable.' Something that is un-movable cannot be moved or shifted, while something that is movable has the ability to be moved or transported with ease. Other antonyms for this word include flexible, agile, adaptable, and mobile. These words imply that an object, person or situation has the ability to adjust and shift positions as necessary. The importance of understanding antonyms is to be able to express yourself more effectively while speaking or writing by using the most accurate vocabulary. A good vocabulary can help you communicate more clearly, accurately, and convincingly in all aspects of life.