Illissa \i(l)-lissa, ill(is)-sa\ as a girl's name is a variant of Alyssa (Greek), and the meaning of Illissa is "rational".

The baby name Illissa sounds like Illyssa, Ellissa, Allissa and Ilissa. Other similar baby names are Allessa, Ilyssa, Elissa, Allyssa, Alliss, Alissa, Allissah, Allisa, Bellissa, Calissa, Delissa, Ellyssa, Illiana, Illia, Illsa, Ilisa, Jalissa, Jelissa, Jolissa, Julissa, Kalissa, Melissa, Mallissa, Malissa and Ulissa.