- illegitimately, illicitly - in a manner disapproved or not allowed by custom; "He acted illegitimately when he increased the rent fourfold"
Antonyms: legitimately, lawfully, licitly
- illegitimately, out of wedlock - of biological parents not married to each other; "this child was born illegitimately"
Antonyms: legitimately
Derived from adjective illegitimate2