Definition from Wiktionary, the free dictionary
Uncertain whether a construction of 'cow' and 'son' or from an alternative meaning which has become overlayered.
cowson (plural cowsons)
- (London slang, chiefly South London) Term of mild to medium abuse in reference to another person or a situation
- That cowson still owes me five quid.
- Millwall lost again. What a cowson.