1523, from Sp. or Port. don,
title of respect, from L. dominus
"lord, master." The university sense is c.1660, originally student slang; underworld sense is 1952, from It. don,
from L.L. domnus,
from L. dominus
). Don Juan
"philanderer" is from the legendary dissolute Sp. nobleman dramatized by Gabriel Tellez in "Convivado de Piedra"
and popularized in Eng. by Lord Byron. The fem. form is Dona