What is another word for be in a world of your own?
Pronunciation: [biː ɪn ɐ wˈɜːld ɒv jɔːɹ ˈə͡ʊn] (IPA) 
There are many synonyms for the phrase "be in a world of your own". Some of these include being immersed, absorbed, lost in thought, deep in contemplation, in a reverie, daydreaming, and lost in your own world. Other synonyms include being oblivious, unaware, insular, introspective, self-absorbed, and secluded. These phrases all refer to a state where someone is disconnected from their immediate surroundings and fully focused on their own thoughts, feelings, or interests. Whether it's through creative pursuits, meditation, or introspection, being in a world of your own can be both a fulfilling and isolating experience.
