Bakayarou is not a swear word, but a name describing someone who is fool because he will point to a deer and call it a horse. Exact translation is deer-horse (fool) infront (of me). In Japanese it has a deeper meaning in terms of the insult.

It means to describe someone who has no integrity, no morals, hypocrites, ppl who are giving crocodile tears, insincere within, a despicable person who could lie through their teeth because they can point to a deer and call it a horse. That's why the basic translation is Fool or Asshole, but it has a deeper meaning.