British - drunk
American - really mad

1) To be extremely angry

2) To be heavily intoxicated with alcohol to the point of not knowing where you are.

3) Past verb of piss.

Annoyed and angered.

Drunk off your ass.

Drunk. Very drunk.

Slight intoxication through alcohol consumption. Typically characterised by a slight sense of drunkenness but none of the more advanced symptoms such as a reduction in inhibitions, loss of self control or inability to respond to questions. One step above sober on the scale of drunkenness and one step below steaming.

1. to be very drunk
2. to be very angry

I know you may have heard this before, but pissed, in Britain, means to be drunk.