A little learning is a dangerous thing A small amount of knowledge can cause people to think they are more expert than they really are.eg. he said he'd done a course on home electrics, but when he tried to mend my table lamp, he fused all the lights! I think a little learning is a dangerous thing
Agony aunt An agony aunt is a newspaper columnist who gives advice to people having problems, especially personal ones.
All and sundry This idiom is a way of emphasising 'all', like saying 'each and every one'
All bets are off (USA) If all bets are off, then agreements that have been made no longer apply
Can't do it for toffee If you can't so something for toffee, you are incapable of doing something properly or to any sort of standard
Cat's lick (Scot) A cat's lick is a very quick wash
Class act Someone who's a class act is exceptional in what they do
Scattered to the four winds If something's scattered to the four winds, it goes out in all directions
Screw loose If someone has a screw loose, they are crazy