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

1.
zerstreut, geistesabwesend
having or showing a habitually forgetful or inattentive disposition
:
•
He's so absent-minded that he often forgets where he parked his car.
Er ist so zerstreut, dass er oft vergisst, wo er sein Auto geparkt hat.
•
Her absent-minded professor walked into the wrong classroom.
Ihr zerstreuter Professor ging in das falsche Klassenzimmer.