n. A word derived from the same root, or with the same sound, as another word.
the GNU version of the Collaborative International Dictionary of English
n. A paronymous word.
The Century Dictionary and Cyclopedia
n. A word which is a derivative from another.
n. A word of one language which translates a word of another with only a difference of termination or other slight change, as English canal for the Latin canalis: opposed to heteronym.
Word Usage
"My listings like "looking to get tarred and pleasured" and "Searching for a heroine to do the paronym of this sentence's lexical subject" kept getting flagged."