Why is gokodu used as a synonym (euphemism?) for yakuza?

I've got very little knowledge about the Japanese language so apologies in advance.

I'm playing the Yakuza videogames and when discussing the yakuza, characters say gokudo, (which I understand as a sort of euphemism meaning 'evil'), instead of actually saying 'yakuza', as is written in the subtitles.

Why is this? What different connotations does each word have? Is there perhaps a taboo surrounding these words?

Thanks in advance.