be lost in (something)(redirected from am lost in)
be lost in (something)
To be fully and deeply engrossed in something, such as a thought or idea, often to such a degree as to be unaware of or insensitive to the outside world. It's no use trying to talk to Helen when she's lost in thought like that; it's as if we don't even exist! I've been lost in this show all day and didn't even hear the phone ring when you called.
See also: lost