undistinguished vs run-of-the-mine

undistinguished and run-of-the-mine both are adjectives.

Word	Noun	Adjective	Verb	Adverb
undistinguished	No	Yes	No	No
run-of-the-mine	No	Yes	No	No

As adjectives, undistinguished and run-of-the-mine are synonyms defined as:

undistinguished and run-of-the-mine: not special in any way; lacking distinction

Other synonyms of undistinguished include mine run, run-of-the-mill, unexceptional.

undistinguished (adjective)	run-of-the-mine (adjective)
not special in any way; lacking distinction	not special in any way; lacking distinction