clue·less
adjective/ˈkluːləs/
/ˈkluːləs/
(informal, disapproving)- very stupid; not able to understand or to do something
很愚蠢的；（对某事）不懂的，无能的 - He's completely clueless about computers.
他对计算机一窍不通。 - Henry was a young and very clueless officer.
亨利是一位年轻且非常无知的军官。
- He's completely clueless about computers.