this phrase contains two words:
1. Wicked- Very
2. Retarded- Stupid
Therefore it means very stupid
O MAN SULLY you're wicked retahded
1. Used to reference something good or exceptional
2. Used negatively in response to the rest of the world's obsession/hatred of the Boston area accent.
3. Used to descride how your face looks after I fight you for critisizing my accent despite being unprovoked.
"That homerun Ortiz hit was wicked retahded", "Why does everyone act wicked retahded when it comes to our accent?", "Hey Mike, look what I just did to this douchebags face, he looks wicked retahded!"