cold gives us the contemporary gay definition for a Wolf. But the term goes back to the 1920s in the US, most popular in the 30s and 40s, when it originally meant a straight man who was aggressive toward women.
Women were warned to watch out for Wolves, and the term "Wolf Whistle" meant the distinctive double whistle a man would make as a good-looking woman walked by. I even remember cars that had Wolf Whistle horns retrofitted to make that sound.
You may also remember some 30s & 40s cartoons (from TV broadcasts, of course) where Wolf characters are featured, especially in Warner Brothers Looney Toons. They're usually portrayed as an actual wolf walking on 2 feet, but dressed very slick, sometimes in a period Zoot Suit with a long pocket watch chain and wide-brimmed hat, chasing females. Several are featured in Bug Bunny cartoons.