absent-minded
US /ˌæb.səntˈmaɪn.dɪd/
UK /ˌæb.səntˈmaɪn.dɪd/

1.
心不在焉的, 健忘的
having or showing a habitually forgetful or inattentive disposition
:
•
He's so absent-minded that he often forgets where he parked his car.
他太心不在焉了,经常忘记把车停在哪里。
•
Her absent-minded professor walked into the wrong classroom.
她心不在焉的教授走错了教室。