Aaaaand yet another hilariously bad official translation. This time, they see a word they don't understand and they just keep it that way - just like nowadays fan translators of Japanese. Grumete" is not an insult, is the Spanish word for a cabin boy or an aprentice sailor. And yes, there is an English word for it, "grommet", even if nowadays it is mostly used for young sportsmen. The moar you know.