can't do something for toffee
(British informal) if you say that someone can't do something for toffee, you mean that they are extremely bad at doing that thing Annie couldn't act for toffee, but she still got a part in the school play.
toffee-nosed
(British & Australian informal) toffee-nosed people think that they are better than other people, especially people of a lower social class She's much nicer than that toffee-nosed sister of hers.