The phrase "out-of-the-world" is typically used to describe something that is incredibly amazing or unusual. There are a variety of synonyms that can be used in place of this phrase to convey a similar meaning. Some of the most common synonyms for "out-of-the-world" include "spectacular," "extraordinary," "remarkable," "unbelievable," "fantastic," "marvelous," "incredible," and "astounding." Each of these words brings its own unique connotation and tone, allowing the speaker or writer to choose a synonym that best fits the situation and context. Using these synonyms can help add variety and depth to language and better convey the desired tone or feeling.