Tone and formality of the word "loth"

Question

On this Economist article, the journalist uses the word loth in the following sentence:

(...) they are loth to do this.

Checking the definition online I found: adj. unwilling; reluctant

I get the meaning completely.

• But is this a formal, obscure word?
• Is it used orally (outside of academic or formal circles)?
• What is the tone that it expresses?

I have never come across it and was curious to understand.

Answer 1

Loth is just another spelling of loath. It's not even marked archaic in my dictionaries.