This is an American English term but I really, really dislike it. It is such an unattractive way to describe a pair of trousers. Who would openly admit to wanting to wear a pair of slacks? When I think of ‘slacks’ I think of elasticated nylon trousers with a crease neatly ironed down the front. I think of Harold and Hilda from Ever Decreasing Circles (1980s Sunday evening sit com). I think of Marks and Spencers.
If you google ‘slacks’ the definition it thows back at you is ‘casual trousers’. Perhaps it is partly because I don’ t wear trousers very often (I only wear jeans about twice a year and trousers perhaps once a year) that I dislike the word ‘slacks’. The word is unattractive. The item of clothing it describes is unattractive.
Incidentally, I also dislike the word ‘pants’ (as in trousers). It makes them sound completely unsexy (but slightly more sexy than slacks).
Who would want to be seen out in their pants or slacks? Who dons their slacks for a night on the town? Who ever met their future love interest in a pair of slacks? Exactly!