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1.
a demeaning term used to describe someone whose penis size would otherwise be considered miniscule
Shut up rat dick!
Hey rat dick, go suck a nut you cockgobbler.
by Lee Boy March 09, 2003
 
2.
Small and insignificant, not worthy of consideration.
Its just a 'Rat Dick' company, unlikely to accomplish anything or pose a threat.
by txtornado99 August 25, 2008