The reason I ask is that the feeling evoked by the term badass feels to me like a human universal, so ought to have synonyms in any era. Trying to confirm my hypothesis, I hunted through the Online Etymology Dictionary, where I hoped to find archaic substitutes, which unforunately did not provide me a direct history for badass. Instead, it directed me toward "bad + ass", which feels sort of strange to me since I'm not sure you can get the feeling of this word by breaking it down into constituents — one needs real-life examples, really. The "bad" of badass seemed relevant towards the meaning, though, and here's what the Etymology Dictionary has to say:
[Bad's] [i]ronic use as a word of approval is said to be at least since 1890s orally, originally in Black Eng., emerging in print 1928 in a jazz context. It might have emerged from the ambivalence of expressions like bad nigger, used as a term of reproach by whites, but among blacks sometimes representing one who stood up to injustice, but in the U.S. West bad man also had a certain ambivalence:
These are the men who do most of the killing in frontier communities, yet it is a noteworthy fact that the men who are killed generally deserve their fate. [Farmer & Henley]
Right, so bad and hence badass is a modern term, with the former appearing no earlier than 1928, and the latter having a '70s era feel for me. My question is, what were people using to describe badasses like William the Conqueror, William Wallace, and Samuel Whittemorein their time?
Best Answer
In the movie Patton, General George Patton tells Erwin Rommel how he defeated him. "Rommel, you magnificent bastard, I read your book."
I can't tell if the usage is actually from the WWII era, but the movie came out the 1970s, and the term has pretty much the same implications as badass when it's used as a term of admiration. (See Magnificent Bastard.)
However, examination of Patton's actual quotes suggests that he commonly used the term bastard, so it's plausible.