from Wiktionary, Creative Commons Attribution/Share-Alike License
- v. To bump lightly, whether accidentally or purposefully.
- v. to water down, dumb down or especially weaken, particularly in video games.
From automobile racing; to bump another car (ca. 1950's?). From NERF® ("non-expanding recreational foam"), a range of toys made of soft foam, ineffective as actual weapons (1969). (Wiktionary)