Green’s Dictionary of Slang

1. pertaining to bribery, usu. accepting but occas. giving bribes.

1917		‘A-No. 1’ From Coast to Coast with Jack London 73: This would have meant that we would have to make a clean breast of our transaction with the grafting brakeman.
1959		H. Salisbury Shook-Up Generation (1961) 162: The profound effect which the spectacle of the grafting officer makes on the street boy.

2. describing those who acquire political gain through bribery and extortion.

1935		(con. 1920s) J.T. Farrell Judgement Day in Studs Lonigan (1936) 525: We got to get a strong man [...] to kick out the bankers and grafting politicians and racketeers.
1952		C. Hamilton Men of the Und. 307: New anti-gambling laws [...] ensure a bigger rakeoff to grafting politicians and cops.
1974		Coward et al. Psychologist With a Gun 43: This was 1959, and conditions were different. [...]. In those days, while Harlemites might have thought the policeman was often ‘a grafting crook,’ they would call him when in trouble.