be a dead loss

be a dead loss 

1. (informal) if something or someone is a dead loss, they disappoint you because they are of bad quality or because they are not able to do what you want them to do The meeting was a dead loss. We didn't come to a single decision. He may have been a great poet, but he was a dead loss as a husband.

2. (informal) to be very bad at a particular activity or subject (sometimes + at ) I was an absolute dead loss at sport when I was at school.

See also: dead, loss