A person with a piss poor attitude.
Always looking at things thru skeptical eyes, expecting the worst.
Like Debbie Downer but knowingly irritating people who are trying to be positive.
The pissamist is particularly irritating to the visionary who is incapable of seeing details as they dream of new outlandish things to do without understanding or considering the magnitude of effort or cost to achieve their new dream.

A term used to reference cannabis/marijuana/weed.

Someone who turns into an optimist when pissed and a pessimist when sober.