The term 'Spaghetti Western Director' refers to Sergio Leone, an Italian film director who is best known for his work in the Spaghetti Western genre. Leone directed a number of iconic films in the genre, including 'A Fistful of Dollars', 'For a Few Dollars More', and 'The Good, The Bad, and The Ugly'. He is widely considered to be one of the most influential directors in the history of cinema.