Someone who continuously one-ups someone else.
On the show "The Price is Right", when someone bids 600, there's always somebody who has to bid 601. "I just adopted a dog from the pound." "Well I just rescued a whole litter of puppies from the sewer." "Dude, don't be a 601-er."
by Nicoliosis April 14, 2006
One of those people that always try to one-up you (named after those pesky folk on "The Price is Right" who always outbid their opponants by $1)
... and then she's all, "well my car gots chrome rims AND tinted windows." And I was like, "601er best be gettin' outta my face."
by elsenore July 14, 2003