not worth a whistle

not worth a whistle

Worthless or useless to such an extent that the person or thing in question does not merit the effort of being whistled at. I wouldn't have too much faith in Bobby—he's not worth a whistle, and this business will probably just become another in a long line of failures for him. I was so excited when my grandpa said he'd give me his car, but this old clunker isn't worth a whistle.
See also: not, whistle, worth