Best definition
Derived from the activities of loudmouthed, cockney, sexist, racist, tactless, west ham loving alcoholic.
Often seen masquerading himself as a

sales exec and with delusions of management skills.
Someone prone to extended periods of absence from place of employment followed by highly creative excuses. Usually after payday or westham games.

To pull a Wellsie.

Wait until pay day. Ideally close to a West Ham game.

Get totally blotto and maybe get into a fight.

Dont phone in sick the first day. Instead use this time to think of an ellaborate excuse to use on your glorious return to work.