
Zone out
Lack of focus
Used when someone is not focusing on what they should be, often unintentionally.

Sorry, can you repeat that? I zoned out for a moment.
Mind wandering
Can indicate daydreaming or getting lost in thoughts unrelated to the present.

While reading, I keep zoning out and thinking about the weekend.
Not negative
Zoning out isn't always bad. Sometimes it's a natural response to a monotonous activity.

It's okay to zone out while jogging; it can be quite meditative.
WordUp Chrome Extension
As you browse the web instantly look up words you don’t know.
Get Chrome Extension