Combination of two words pissed and hard. Can be misheard as pisshead but holds an entirely different meaning. Meaning to get pissed (become intoxicated by consumption of alcohol) and acting hard (starting fights and generally being a twat).
Pissard is usually achieved by drinking copious amounts of vodka which will induce violent behaviour or generally being a chav who drinks cider will suffice.
1. "Hey fancy getting pissard this weekend and fighting some people?"