He fights windmills.
More Hungarian Proverbs:
Sheepskin coat to sheepskin coat, cloth coat to cloth coat.Hungarian
You try to trade at a deserted place.
Hungarian
One should not stir the shit as it will be even more stinking.
Hungarian
Goo tool means half the work.
Hungarian
He is as impertinent as a fly at the market.
Hungarian
The pitcher goes so long to the well, until it breaks.
Hungarian