Main Entry: il·le·git·i·mate

Pronunciation: \-ˈji-tə-mət\

Function: adjective

Date: 1536

1 : not recognized as lawful offspring; specifically : born of parents not married to each other
2 : not rightly deduced or inferred : illogical
3 : departing from the regular : erratic
4 a : not sanctioned by law : illegal b : not authorized by good usage c of a taxon : published but not in accordance with the rules of the relevant international code

— il·le·git·i·mate·ly adverb