in (one's) own (little) world
Consumed by one's thoughts, imagination, etc., to such a degree that one is unaware of or insensitive to one's surroundings or the outside world in general. It's no use trying to talk to Helen about something like this—she's always in her own little world. Sorry, what did you say? I was in my own little world there. A: "Hey, did you hear the phone ring?" B: "Oh wow, no, I didn't. I guess I'm in my own world or something."
Farlex Dictionary of Idioms. © 2024 Farlex, Inc, all rights reserved.
in one's own world
Also, in one's own little world; in a world of one's own. In deep thought or concentration. For example, Luanne was really in her own world at the meeting this morning, or Like many mathematicians, Bill lives in his own little world, or Bob's in a world of his own when he's listening to music. [Late 1500s]
The American Heritage® Dictionary of Idioms by Christine Ammer. Copyright © 2003, 1997 by The Christine Ammer 1992 Trust. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.