Learn Turkish: O insafsız patron hiç avans verir mi? - Would that cruel boss ever give an advance payment?

This is the core of rhetorical strong negation. When you use hiç (ever) with a positive aorist question like verir mi, you are not asking for information. You are making a rhetorical statement implying there is absolutely no way he would give an advance.

The English translation uses "would," but verir is in the aorist (simple present) tense. Why use the aorist here?

In Turkish, the aorist tense is heavily used to talk about someone's general character, habits, or typical behavior. By asking verir mi, you are asking if it is in his nature to give an advance. English naturally expresses this disbelief about someone's character using "Would he ever..."

What is the root of the word insafsız?

It comes from the word insaf, which means mercy, conscience, or a sense of fairness. By adding the "without" suffix -sız, it becomes insafsız, meaning merciless, unfair, or cruel.

Can avans be used for other types of "advances" like a military advancing?

No, in Turkish, avans is borrowed from French and almost exclusively refers to a financial advance, like an advance payment on a salary. For physical or metaphorical advancing, you would use words based on ileri (forward), such as ilerleme.