What is the meaning of "Al-Musrifin" (the extravagant/profligate)? And is one who spends a million Riyals on a wedding party considered extravagant, or does that fall under "But as for the favor of your Lord, report it"?

Scholars have defined extravagance (Israf) in multiple ways, including: ignorance of the extent of rights, spending on what Allah has forbidden, exceeding the limit for one's like, or exceeding moderation and balance, and that which does not entail immediate praise or future reward.

Most scholars agree that extravagance is not limited to spending on forbidden things, but also includes spending on permissible things if it exceeds the bounds of moderation and custom. Its precise definition varies according to people's circumstances, whether rich or poor.

It is not possible to determine whether the mentioned amount constitutes extravagance without knowing the currency and the financial situation of the spender. Among the etiquettes of a wedding feast is that it should not be exclusive to the wealthy. If the amount is spent to feed a large number of needy people, then there is no harm; rather, it is a good deed for which its doer will be rewarded.