Funny enough, the origin of that character is 姦 - which goes all the way back to the earliest forms of Chinese writing (the bronze inscriptions) and was a pictogram of 3 women together (see here), which represented "evil, treacherous, scheming, traitor, adulterer" and similar. 奸 was a later variant form with same meaning (the 干 was added as a phonetic component, and 3 女 were reduced to just 1), which was later adopted as the simplified form of traditional 姦.