For the sake of historical bullet points, know that the Oxford English Dictionary defined “douchebag” as “an unattractive or boring person.” In 1967, the Journal of American Speech specified that douchebag applied to “an unattractive coed.” And a year later, the Historical Dictionary of American Slang offered the most obliquely comic definition — “a person who always does the wrong thing.”
So to sum up, douchebag was once an insult directed towards an ugly girl, and it’s since become a niche variant of asshole (Geoffery Nunberg notes in his new book Ascent of the A-Word that “a lot of people don’t have douchebag in their vocabularies at all, particularly women”).
But how the term douche, which is French for shower, came to signify what user JLTJ described on Urban Dictionary as one who will “learn to play parts of songs on the guitar to attract girls” follows a trajectory I’m not sure can be traced via OED citations. That said, what’re more interesting than anything a responsible lexicographer can drum up, in this case, are the ridiculous definitions posted on Urban Dictionary.
JLTJ goes on to explain that “occasionally [a douche] will sing along to songs on the radio and look at others riding with them to make sure they are paying attention to the fact that they are singing.” These weirdly specific definitions, which are subject to simple modus tollens takedowns (Yes, Louis learned to play Neutral Milk Hotel’s “King of Carrot Flowers,” but he’s a total sweetheart!), nonetheless point to an area in which language might be well served by the democratic internet.
Urban Dictionary certainly has its hang-ups. The first entry for my first name reads, “Someone who is unusually [sic] hung. People with the name James are generally known for their good looks (especially the eyes) and women are just simply attracted to them.”
I mean, my mom says I’m handsome? The real problems tend to pop up with racist or homophobic slurs (see “figure skating”). Others are just meaningless (the top entry for “taco” reads, “the best food ever made,” with the example sentence “Holy sh-t tacos are good.”).
However, words like douche or douchebag, which don’t share the same kind of specificity with words like “anachronistic” or “praying mantis,” are well served by a community of teenagers rambling about what a douche means to them. There are plenty of mentions of backwards hats and pink polo shirts adjectives like “obnoxious” and “self-promoting” peppered throughout. Someone simply wrote “George W. Bush.” If anything, examples of douchey traits or actions are more telling than proper blanket definitions.
Slang, more than any other category of language, is so amorphous that the only thing that matters is whether the person on the other end knows what you’re saying. Regardless of whether a bit of slang has a specific etymological provenance, it’s not really relevant because there’s no confusion caused by misidentifying someone as a douche. If someone’s conceited, then calling them “oblivious” doesn’t make sense. But calling them a douche doesn’t have the same guidelines. It’s equal parts meaningless and spot-on, and it’ll tip a little bit one way or the other depending on who you’re describing and to whom.
For douche, therefore, look not to the well-edited dictionaries, but to the proliferation of chatter on Urban Dictionary and other amateur language blogs. Because the best answer to What is a douche? may just be, You’ll know him when he stares you down as he sings along to the radio, pausing briefly to profess his love for tacos.