undistinguishedpast participle Functions as a past-participle adjective derived from the verb "distinguish" with negative prefix.
undistinguishpast participle Past participle form “undistinguished” is used as a lexicalised qualitative adjective.
Despite his undistinguished appearance, he was a brilliant scholar.
Несмотря на его непримечательную внешность, он был выдающимся учёным.