Learn German: Ich bezahle die Rechnung nicht, zumal das Fleisch zäh und trocken ist. - I am not paying the bill, especially since the meat is tough and dry.

The word zumal is a subordinating conjunction meaning "especially since" or "particularly because." Like other subordinating conjunctions (such as weil or dass), it forces the conjugated verb in its clause, which is ist here, to the very end of the sentence.

Can I use weil or da instead of zumal here?

You could, but you would lose some meaning. While weil and da simply mean "because" or "since," zumal emphasizes that this is an especially strong or decisive reason. It acts like "because, on top of everything else..."

Why is nicht placed at the very end of the first clause?

When negating an entire action or verb (here, paying the bill), nicht generally moves to the end of the clause. It sits right before the comma because it only belongs to the main clause (Ich bezahle die Rechnung nicht) and cannot cross over into the zumal clause.

Why is the word zäh used to describe the meat instead of hart?

When talking about food, zäh specifically means "tough" or "chewy," which is exactly how you describe overcooked or bad meat. If you used hart (hard), it would sound like the meat is literally hard as a rock, like a frozen block or a brick.