A combination of the words: hater and flagger. A person who flags an ad, numerous times, until it is removed from Craigslist; purposely. The reason for doing this is either: to be the only one to respond to the ad, before they cause it to be removed. Giving the appearance, to the person who put the ad up, the Hagger was the only person interested, and therefore the item and / or service should go to him/her. Or, the hagger has a service / product similar to the original poster, but of lesser value, and doesn't want to lose business because of the original poster, so eliminates the competition.
I keep trying to sell my iphone 4s on Craigslist, but minutes after I put the ad up, it's taking down. I keep getting the same guy, saying he'll buy it for 300. He's got to be a hagger!