expression
distracted; absent-minded; physically present but mentally elsewhere
Describes a state where one's body is present but the mind is wandering; often used when someone is not paying attention or is preoccupied.
授業中、彼は心ここにあらずで、窓の外を見ていた。
During class, he was distracted and staring out the window.
会議で心ここにあらずの様子だった。
He seemed absent-minded at the meeting.