out to lunch
Away eating lunch or for a midday break; especially, away from work or a job.
She's out to lunch right now, but you may leave her a note.
noun
A light meal usually eaten around midday, notably when not as main meal of the day.
We made an odd party before the arrival of the Ten, particularly when the Celebrity dropped in for lunch or dinner.
A break in play between the first and second sessions.
Any small meal, especially one eaten at a social gathering.
After the funeral there was a lunch for those who didn't go to the cemetery.
“Oh, you mustn’t dream of going home without your tea,” cried Anne in distress. “I’ll get it right off—I’ll go and put the tea down this very minute.” “I must go home,” repeated Diana, stupidly but determinedly. “Let me get you a lunch anyhow,” implored Anne. “Let me give you a bit of fruit-cake and some of the cherry preserves. […]”
A thin piece or hunk (of bread, meat, etc.)
verb
To eat lunch.
I like to lunch in Italian restaurants.
The gentleman had left for London after lunch. Yes, alone; but he had lunched in the hotel with a lady.
To treat to lunch.
We dined him, we lunched him, we were photographed in his company by flashlight.