The word "grifter" is believed to have originated from American criminal underworld slang around the early 1900s, likely as a variant of the word "grafter" (a slightly older slang term for a person who acquired money dishonestly or was a swindler, such as con artists, pickpockets, and card sharks).  The word may have also derived from a combination of "grafter" and "drifter" reflecting the rootless nature of many con artists.  It first appeared in print around 1915 and initially referred to a con artist or non-violent criminal, particularly those associated with carnivals and circuses.  The term has evolved from its criminal origins to describe anyone perceived as self-serving or deceptive, especially in politics, where it is used as an insult to accuse someone of using the political process to enrich themselves.  

According to the Oxford English Dictionary (OED), the first known use of "grifter" is in 1915, in the writings of George Bronson-Howard. 

Examples of "grifter" used in a sentence: 
"The con artist was a skilled grifter, convincing people to invest in a fake business before disappearing with their money."  
"The grifter used charm to get close to his elderly neighbor, and soon the neighbor's savings were gone."  
"Critics accused the politician of being a grifter, alleging that they engaged in dishonest practices to enrich themselves." 
"Below that, thousands of comments tumble in, calling him a terrorist and a grifter." 
"So while Fuentes may survive longer as a true believer, he'll never gain as much money and influence as the grifters." 

Just the facts:

GRIFT Definition & Meaning - Merriam-Webster

What's the difference between 'grift' and 'graft'? | Merriam-Webster

Grifter etymology - Google Search

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