野獣 | A sexual predator, someone who is not just a rapist but also physically wild or animalistic in their lust. |
畜生 | Comes from a word for beast, but it’s used just like asshole! You asshole! Fuck! |
獣 | Used about literal animals – not necessarily the hugest or scariest, but animals that are both violent AND unclean, like the hyena. Also used about people who behave like those animals. |
猛獣 | A big scary animal – lion, bear. Not used about people even metaphorically. |