Green’s Dictionary of Slang

graf n.

graffitti; also attrib.

1994		Source 54: Graf was always a part of hip-hop.
1998		Source Oct. 73: A nationally known graf artist who has work featured in the Smithsonian.
2000		Hip-Hop Connection Jan./Feb. 94: I like the anonymity graf provides.
2014		A. Fox-Lerner ‘Traces of a Name’ in ThugLit Mar. [ebook] Hit by a train. Not an unheard of way for a graff writer to die.

In compounds

graf-head (n.) (also graffer) [-head sfx (3)]

(orig. US black) a graffiti-artist.

2003		‘Hot Spots’ in Millimeter 1 May 🌐 Collaborating with graffiti artists Skwerm, Sasuke, and Frek, Motion Theory creates a graf head’s vision of heaven for this Asian campaign for Nike’s Presto line.
2004		Observer Cash 3 Oct. 10: Your typical successful ‘graffer’ is now in his thirties.