Fraud is a noun for the practice of lying to someone in order to gain something, either money or some other beneficial intangible. It is also the word for a person who commits fraud. Another term for this kind of person is a fraudster. This term is mainly used in British English, but can be found in some US publications as well.
Defraud is a verb that describes a practice of lying to someone or an institution to steal money specifically. This includes acts like identity theft and electronic hacking.
A person who defrauds someone else is a defrauder.
Examples
Attorney General Loretta E. Lynch and the Department of Health and Human Services (HHS) Secretary Sylvia Matthew Burwell announced yesterday the largest ever healthcare fraud takedown. [FOX Business]
Two days after arrest of chit fund fraudster who duped hundreds of crores of rupees, police said accused worked in different small companies and rose to become a multi-millionaire through unlawful means. [The Times of India]
Earlier in the day the children’s barrister Christopher Withers told the court Mrs Rinehart executed a “complex and cunning plan” to defraud her children of the assets and made calculated inclusions in the deeds that unbeknownst to the children, bound them to arbitration. [Sydney Morning Herald]
A defrauder intercepted the credit card information contained in the card’s magnetic strip and used it to make a fake credit card, which Heaps said is as simple as a trip to Home Depot for some supplies. [Gazette Net]