Why did 摩羅 also come to mean penis?


Is there any further implication to be gleaned from this and how did this
meaning come to be? Is there any suggestion that the male genitals are somehow
an obstacle to enlightenment?




Excerpt from 日本国語大辞典 entry:

> まら 【魔羅・摩羅】
>
> **(1)** 「ま（魔）(1)」に同じ。
>
> ＊却癈忘記〔１２３５〕下「勤行之人の魔道に堕ると、世間に人のいふ事、甚謂有事也。魔と者具には魔羅と云ふ」
>
> **(2)** （(1)から転じたとも、排泄する意の「まる」の交替形ともいう）陰茎をいう。もと僧侶が用いた語。
>
> ＊霊異記〔８１０〜８２４〕中・一一「卒爾に（マラ）に蟻著きて嚼み〈国会図書館本訓釈 万良〉」

That means, the "penis" sense may have come from buddhist _māra_ , or the verb
まる "excrete", or confusion between both.

