Gams

Gams - "legs," 1781, ult. from M.E. gamb "leg," from O.N.Fr. (see gammon). Now, in Amer.Eng. slang, especially of pretty women, but this was not the original sense. (Link)

I've heard this word only a few times; a coworker once used it in a joking comment. Today, the old guy from my gym used it and it was kind of funny.

I had been leaving the gym. The old guy, harmless guy who's often there and I've talked to many times before, was talking to someone at the entrance when he looked at me in surprise and said, "damn! you look good in clothes!" I laughed and said thank you and continued on my way. I was wearing a skirt, and he exclaimed, "wow, you've got gams!" Again, I laughed and waved goodbye.

Use of the word gams makes me think of the swinging 20s or 30s, when men wore suits all the time and women wore dresses all the time. I'm not entirely sure if its a designation to be offended by, but its an interesting word.

And, as mightyredpen pointed out, its hard to pull it off if you're not Dick Tracy.