According to Wiktionary, the etymology of "shark" beyond Middle English is unknown – and even there, we only see it once in 1442.

Edit: the Online Etymology Dictionary has more.

Even the word itself looks like a shark

Sharks don't "infest" waters, they LIVE there.

They just look sharky, you know?

Similarly, whoever named “scabies” really nailed it

I study languages for fun and though English can be grating at this point (native speaker but typically in a Spanish/Mandarin environment) one thing I’ll give it is a lot of words do sound like what they mean — and though I’m surely biased as a native speaker there are some words that are just very satisfying:

• boom
• crispy
• crunch
• cut
• slice
• tap

…probably a lot more I can’t think of.

I dunno, that one kinda looks like a toothy potato.

Even in Mandarin the name（鲨鱼） is a homophone with the word for 'kill' 杀

Hai!