Noun: An involuntary erection whilst sitting fully clothed capable of casting a noticable shadow on the torso of the offender.
Having beers around the fire one night Quinton popped an absolutely absurd Shadowcaster.
by Alcatrazz69 October 30, 2012
2 more definitions
An erect (usually female) nipple that protrudes through clothing enough to cast a shadow in full light.
Dude, check out the shadow casters on that chick's fun bags!
by un_malpaso October 30, 2008
A pest, a nuisance, someone who follows you around constantly, but poses no danger like a stalker.
That guy is such a shadow caster. Every time I turn around, there he is...all up in my face.
by Anonymous June 20, 2003