in addition to meaning more rad, this can also mean the opposite.  Radder can describe a short, on the brink of being a midget girl who is very loud and obnoxious, mainly in public places. attracts attention to where attention is not wanted.  Usually a Radder has heavy make up and dresses towards to 80's revival.
-Damn that Radder is obnoxious.
-Let's get up and move over to that table, so no one will look over and see us near her.
-Let's get up and move over to that table, so no one will look over and see us near her.
by Ross Welborn January 17, 2005
 Get the Raddermug.
Get the Raddermug. Used to describe a person, place, thing, situation, feeling, action, or thought that is overwhelmingly cool and/or hella awesome.
by Sir Raddxcore Radish July 7, 2008
 Get the Radder Than the Raddest Radishmug.
Get the Radder Than the Raddest Radishmug. a person that is Definitely Rad; an association of Gnarly People; believers of the Rad Harmony Faith; People that are allergic to Lame; Epic Lame-Slayers from Slutty Utah; anyone Awesome;
"Priest Rev. Jonson, Kung-Boo, and the Slutty Martinez Brothers are Def-Radder Lame-Slayers, and the Fathers of Rad Harmony!"
"Def-Radder's do not, or ever will listen to any Usta-Groover"
"That Def-Radder is the Gnarliest Mother Effer I ever Met!"
"Def-Radder's do not, or ever will listen to any Usta-Groover"
"That Def-Radder is the Gnarliest Mother Effer I ever Met!"
by Don_Mayhem January 27, 2010
 Get the Def-Raddermug.
Get the Def-Raddermug. 