Swindler
Con Artist, Scammer
noun
You know that 詐欺 is "fraud." An expert in fraud is someone who does this it lot, and possibly for a living. That's a swindler, a con artist, or a scammer.
This is a jukugo word that uses the on'yomi readings of the kanji. You should be able to read this on your own. Will help to know the reading of 詐欺 as well.
派手にお金を使っているなぁと思っていたら、詐欺師だったんですね！
I thought you are a big spender, and you turned out to be a con artist.
不動産詐欺師というものが結構いるらしい。
I heard that there are quite a few real estate scammers out there.
「ねぇ、今俺のこと、嘘つきって言った？」「そうは言ってないけど、詐欺師とは言ったよ。」
"Hey, did you just call me a liar?" "No, but I called you a swindler."