A person from the Niles region of Southwest Michigan that is known as one of the dregs of society. Gritters are usually known for being unkempt and wearing pajamas to Walmart, and being of a lower IQ, while thinking they are some sort of dirtbag Patriarche.
The female version is a Gritta, and a particularly well known Gritter, with the proper pedigree is known as a Legacy Gritter
Someone taking a hit for the team by fucking council housing lasses in order to keep them off the streets, therefore stop them getting knocked up by other council housing clowns
"Grattering", or having a "gratter" is a term for a person, who uses social networking to meet several girls, and flirt with them all at the same time... Or you can even have individual gratters. To "gratter" you have to know them in some way. It is harmless flirting that means nothing, normally, but in some cases, leads to an actual relationship.
*on msn* Gratter: "Hey baby, you were lookingpretty in school today, and you're really nice...:) <3 xx"