It's some one (most likely male) who is attractive, but not like a pretty boy is attractive. Most likely they have long(ish) hair and a some what scruffy appearance and rather built. they are really hot anyways, or just because of it.
Heath Ledger, in "10 things I hate about you" is by definition Ruggedly Handsome.
Hard core exterior with sexy atributes, a kind of lumber jack appeal with scruffy hair.
Ashley: "Man Kyle and James are both ruggedly handsome, but Kyle is clearly the better looking of the two."
Good lookin not pretty boy type
I'm a thug in the club buggin and dancing.I ain't one of them cute niggas I'm Ruggedly Handsome