Family name Наи (Наи 
, Nighy 
) , across the world, is a very rare cognomen. The cognomen Наи is characteristic of Czechia, where it is a rare surname, the United Kingdom, where it is a very rare surname, and Kyrgyzstan. Measured by absolute frequency, it is commonest in the United Kingdom, Czechia, and Russia. Much less frequently, Наи is the forename as well as the last name.