Learn Farsi: تو نمی‌توانی قبل از مات کردن فاتحانه بخندی. - You cannot laugh triumphantly before the checkmate.

It is formed by adding the suffix ـانه (-āne) to the noun/adjective فاتح (fāteh), which means "conqueror" or "victor". The ـانه suffix is used to show manner or similarity, turning the word into an adverb that describes how an action is done. Literally, it means "in the manner of a conqueror".

Why does the sentence end with بخندی instead of the normal present tense می‌خندی?

Because it follows the modal verb نمی‌توانی (you cannot). In Farsi, when you use a modal verb like "can", "must", or "want", the main action verb that follows it must be in the subjunctive mood. For most verbs, this means replacing the میـ (mi-) prefix with a بـ (be-) prefix, giving us بخندی.

Why do we use the full infinitive مات کردن (to checkmate) after قبل از?

In Farsi, when you want to say "before doing [something]", you use قبل از (before) followed directly by the infinitive form of the verb. The infinitive acts like a noun here, similar to an English gerund (an "-ing" word). So, قبل از مات کردن translates literally as "before to checkmate" but means "before checkmating".

Is the word مات in مات کردن only used for playing chess?

Originally, yes, it means "checkmate" in chess! However, in everyday Farsi, the compound verb مات کردن is also commonly used in a figurative way to mean "to completely defeat", "to dumbfound", or "to stun" someone.