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1.
A proper retard. Plays Quake 3 and Halo 2. Talks absolute gibberish and is also a ginja ninja in disguise.
"Smidsy your a proper tard I swear"
by Noodle April 08, 2005
 
2.
An acronym -

"Sorry Mate, I Didn't See You" is a common excuse given by cagers in car-motorcycle accidents.
I had my first smidsy yesterday at the junction..
by larry arizona April 23, 2006