While watching the World Cup, I am always struck by how many opaque idioms the commentators use:
they're under the cosh (they're under pressure)
that's right on the money (the ball is just where he wanted it)
it's kitchen sink time now (the team is throwing everything forward)
he's got his foot to the floor (he's going as fast as he can)
and so on. I pity foreign language learners who are trying to make any sense of this kind of commentary.
Of course, opaque idioms are all around us, and we rarely stop to think about them. My wife recently heard that someone who had been in hospital for a while had 'turned the corner', and she thought that must be bad, as you don't know what's around the corner. But, in fact, 'turn the corner' is used to indicate that things have started to improve, and the person in hospital was now getting better.
Another idiom with an unexpected connotation is 'over the hill'. Logically, climbing a hill is hard work, and once you get to the top and can start going downhill, that should be good news. But in fact we use 'over the hill' to refer to someone who is past it and is no longer able to contribute much.
And one more: I always think that 'purple patch' ought to be something bad, as I associate purple with bruises and things like that. But, in fact, a purple patch is a period of notable success, especially for a writer or a musician. Apparently, it derives from Roman times, when purple was an exquisite colour that only the rich could afford to wear.
Of course, Malay is just the same. I came across ringan tulang (lit. 'light bone'), and I thought that must be bad. In fact it means 'hardworking'.
And in today's Media Permata I saw this: perkara pokok (lit 'tree matter'). Now, what could that mean? There seemed to be nothing about trees in the article! In fact, perkara pokok means 'the crux of the matter'.
Well, perhaps this last one is because pokok ('tree') has a secondary meaning, for it can also mean 'basic', as in gaji pokok ('basic salary'). Nevertheless, it reminds us how opaque idioms can be.