(by extension) exhausted
Example: Used other than as an idiom. Having a face that is the color red.
2004, Robin Chittenden, Birds of Prey of the World, page 31:
A red-faced bird with a striking white head and underside, and black-and-white wings and tail, the Palmnut Vulture lives in tropical forested areas of Africa, often by lakes, rivers, and seashores.
With a red face; flushed, due to emotional or physical causes.
A red-faced John edged his way quietly out of the room.
Coming home late and red-faced every night from the pub is not what I expected of you.
The customer gave a red-faced account of the argument with the waiter.
"I can't for the life of me think where I left the tickets!", she cried out, red-faced.
He collapsed, red-faced from the effort, against the door jamb.