What is the meaning of a man's guardianship over a woman and its reasons, and does his guardianship fall if he does not spend on her?

Guardianship (Qawamah) of men over women means their care, protection, and rectification. The Holy Quran mentions two reasons for this: Allah's preference for men over women in matters such as prophethood and caliphate, and men's spending of their wealth on women. If a man ceases to provide for his wife, his right to guardianship is forfeited. The preference mentioned in the verse refers to the preference of the male gender over the female gender, not the preference of every single man over every single woman.