nondescript

Short definition from Wiktionary

Adjective

1. 1
   Not described (in the academic literature).
2. 2
   Without distinguishing qualities or characteristics.

Noun

1. 1
   A species or other type of creature that has not been previously described or identified.
2. 2
   An undistinguished, unexceptional person or thing.
3. 3
   An unmarked police car.