1. A semen stain on clothing, particularly embarrassing for a male around the groin area. A stain possibly caused by a male accidentally ejaculating on ones self or sexual misadventure.
2. A derogatory term used to describe a person as nothing more than a disgusting semen stain.
1. Oh shit I dropped ice cream on my trousers and its going to look like a wankstain.
1. Get out of my face , you wankstain !
2. That housemate of mine is harder to get rid off than the wankstain on the wall!
3. This mate of mine is a proper wankstain !
n. Insult, mostly British. Used for foolish, dirty or vulnerable people. Derived from wank and wanker, to do with masturbating. Taken literally, a wankstain would be semen staining an item of clothing after masturbation.