Loath - loathe
From Hull AWE
These two words are different in meaning, pronunciation and word class.
Loath, which is sometimes spelt 'loth' (see loath - loth), is an adjective. It means roughly 'unwilling' or 'reluctant' - 'She was loath to confess that she had not done her homework.' It is pronounced with an unvoiced, or 'hard', -th- sound, like the one in think, IPA: /ləʊθ/.
Loathe (with an 'e') is a verb. It means 'to hate', 'to detest' or 'to dislike greatly, with violent feelings'. It is pronounced with a voiced, or 'soft', -th- sound, like the one in the, IPA: /ləʊð/.