space cadet
US /ˈspeɪs ˌkæd.ət/
UK /ˈspeɪs ˌkæd.ət/

1.
怪人, 白日夢者, 心不在焉的人
a person who is out of touch with reality, often appearing dreamy, distracted, or eccentric
:
•
He's such a space cadet, always daydreaming during meetings.
他真是個怪人,開會時老是做白日夢。
•
Sometimes I feel like a space cadet when I forget simple things.
當我忘記簡單的事情時,有時我覺得自己像個怪人。