To give someone a sweet uppercut (in the style of Mortal Kombat.)
Yo, dawg, Plaks is such an asshole; so I gave him a down b and knocked his monkey ass down!
by Jeff May 16, 2004
Upside down b - which if you look at it as a lower case, means p, or methamphetamine. This is a common term used in New Zealand, made famous by Bro'Town.
The letter p is likely to be derived from the main ingredient in methamphetamine, pseudoephedrine.
Eh bro'! I can't believe youse got hooked on upside-down b!
by Rebelmonkeys October 2, 2006
Someone or something thats retarded.
This is an alternative word to retarded.
Lydio: did you see that retard over there he’s really retarded
Dalziel: no don't say that thats rude . That guy is B-down.
Lydio : bet
by Anonymous errors January 23, 2020