a woman, usually (but not necessarily) attractive and with a multitude of potential suitors, that has relationships that averagely last for no longer than a period of seven days. These women are quite treacherous and hard to spot, but if you do manage to detect a One Week Wendy it is highly advised the you steer clear of them. Only masters of female manipulation or those looking for relationships with little emotional investment should seek to court these vile creatures.
Person A: Oh man I'm pumped to go out with that girl i met at the bar last week! She's so hot and smart and we like all the same things!
Person B: Watch out bro, she's a One Week Wendy! She'll be all over you at first but once you hit the seven day mark she'll dump your fat ass so hard you'll be out for a month!