Most often used in the running community, it describes a person who likes to run while wearing all black.
The ninja runner darted across the dark road, barely escaping certain death from an oncoming tractor trailer.
by The Logophile May 4, 2010
A variation of the common childhood game “rock, paper, scissors”. Ninja kills bear, bear kills runner, runner runs past ninja. Therefore, ninja wins over bear, bear wins over runner, runner wins over ninja.
by Sweet Tits with a K March 26, 2019