Real Dictionary

buccaneer
countable noun: A buccaneer was a pirate. Buccaneers often attacked and stole from Spanish ships in the 17th and 18th centuries.
countable noun: If you describe someone as a buccaneer, you mean that they are clever and successful, especially in business, but you do not completely trust them.

buccaneer in American English
a pirate, or sea robber, esp. one who raided along the Spanish coasts of America in the 17th cent.
noun: any of the piratical adventurers who raided Spanish colonies and ships along the American coast in the second half of the 17th century

buccaneer in British English
to be or act like a buccaneer
noun: a pirate, esp one who preyed on the Spanish colonies and shipping in America and the Caribbean in the 17th and 18th centuries