how to say “to refuse” in Hebrew
לְסָרֵב
For example:
אָנוּ שׁוֹמְרִים לְעַצְמֵנוּ אֶת הַזְּכוּת לְסָרֵב שֵׁרוּת לְכָל אָדָם.
We reserve (to ourselves) the right to refuse service to anyone.
Likewise, refusal is סֵרוּב 
listen and repeat, as in the hot issue at the time of the Disengagement from Gaza, סֵרוּב פְּקֻדָּה listen and repeat – refusal of orders.
listen and repeat, as in the hot issue at the time of the Disengagement from Gaza, סֵרוּב פְּקֻדָּה listen and repeat – refusal of orders.