The sources checked do not record Illie as a personal name or give it a meaning.
Affection
Cute
Black, Brown, Gold, White
Any Size
Unisex
English
I
5 Letters
Illy, Ily, Ili
A given name recorded in English, used for girls.
A stage name of the American rapper and producer Sean Combs
Recorded as a rare given name in american english
An English given name
A diminutive formed with the suffix -y, from a Germanic name