Mung bean, also known as mung, moong, mash bean, munggo or monggo,
green gram, golden gram, and
green soy, is the seed of Vigna radiata which is native to
India.
The meaning in Japanese would be something like "Rookie" "Below" "apprentice" in a bad way...
omae
wa aitsurato yuki dare
mo utskuteru da na? Moyashi...
(You can stay here making dolls
snow with them, you know? Moyashi...)