I am trying to translate something from Polish into english.
We have one expression, videlicet: robic komus laske thta literally means to do mercy to somebody, which in english does not make sense.
Situation. Imagine that you are trying to buy something you go to the till and find a shop assistant filing her nails. she can see you standing but pretends not to see you.
Then you go like: Robisz mi laske? meaning are you trying hard to sell me this product? (it is her job to sell you this product, but for some reason she wants to show you that you are of little value) The expression was used in Poland under communism where shop assistants were more important as they controlled what was sold or not (bribes etc.)
I guess that in English we'd probably say something like "Are you busy?" or "Can you help me?" or "If it's not too much trouble". There would probably be a degree of sarcasm that doesn't quite translate.
'To do mercy to somebody'
could mean:
1/. To pardon someone (from a punishment))
2/. Excuse me!
Incidentally I am not being critical as I am sure your English is much better than my Polish, but just for information. You should also capitalse E in the word English (as you have for P in Polish)