Difference between 喰う and 食う？


I understand both are vulgar male forms of eat, but why these two kanji are
basically the same? What means that 口 in there？




The earliest appearances of 喰 in dictionaries are, as @変幻出没 said, those in
[龍龕手鏡（龍龕手鑑）](http://archive.wul.waseda.ac.jp/kosho/ho04/ho04_00789/ho04_00789_0003/ho04_00789_0003_p0065.jpg)
or [新撰字鏡](http://mahoroba.lib.nara-wu.ac.jp/y05/html/675/l/p022.html), but
their definitions are not much same as today's. The meaning they suggested is
like "dine", "dinner" or "have a meal" and likely to be a variant of 飧.

In more recent usages 喰 explicitly represents くう and くらう, contrary to 食 can
also be read たべる or はむ. I'm not sure if the kanji was recycled or reinvented,
but it certainly had some usefulness because pre-modern orthography rarely
used okurigana, making it difficult to distinguish certain homographs. In this
sense, you can also say that 喰 has already lost its reason for existence, but
it's still in use, especially when you want more "bite and booze" feeling or
violent "consuming, devouring" implications.




The earliest appearances of 喰 in dictionaries are, as @変幻出没 said, those in
[龍龕手鏡（龍龕手鑑）](http://archive.wul.waseda.ac.jp/kosho/ho04/ho04_00789/ho04_00789_0003/ho04_00789_0003_p0065.jpg)
or [新撰字鏡](http://mahoroba.lib.nara-wu.ac.jp/y05/html/675/l/p022.html), but
their definitions are not much same as today's. The meaning they suggested is
like "dine", "dinner" or "have a meal" and likely to be a variant of 飧.

In more recent usages 喰 explicitly represents くう and くらう, contrary to 食 can
also be read たべる or はむ. I'm not sure if the kanji was recycled or reinvented,
but it certainly had some usefulness because pre-modern orthography rarely
used okurigana, making it difficult to distinguish certain homographs. In this
sense, you can also say that 喰 has already lost its reason for existence, but
it's still in use, especially when you want more "bite and booze" feeling or
violent "consuming, devouring" implications.

