In the entire world, Nisai (Nisai 
, นิสัย ) is a rare gender-neutral given name. The forename Nisai is characteristic of Thailand, where it is a rare unisex name, Japan, where it is a rare masculine name, and Nigeria, where it is a very rare boy's name. Measured by absolute frequency, it most frequently occurs in Thailand, Japan, and India. Likewise, Nisai is the last name as well as the forename.