Late 16th century; earliest use found in Thomas Bowes (fl. 1579–1589), translator. From well + distinguished, originally after Middle French bien distingué.
Definition of well-distinguished in US English:
well-distinguished
adjectiveˌwɛldɪˈstɪŋɡwɪʃt
Clearly defined; readily separated; distinct.
Origin
Late 16th century; earliest use found in Thomas Bowes (fl. 1579–1589), translator. From well + distinguished, originally after Middle French bien distingué.