loath vs. loathe  

This is a situation in which silent E helps determine not only pronunciation, but meaning as well. The word loath (which is an adjective meaning “unwilling or reluctant”) is primarily pronounced /loʊθ/ (rhyming with both), while loathe (a verb meaning “to detest, hate, or feel disgust for”) is pronounced /loʊð/ (rhyming with clothe).

(It’s worth mentioning that loth is an acceptable variant spelling of loath, and it helps eliminate a lot of this confusion; however, it is less common, and some may consider it to be incorrect.)

However, to add extra confusion, some speakers pronounce loath the same way as loathe, choosing to use the “softer” /ð/ for both words; this is an accepted variant pronunciation that is present in most dictionary entries for the word. It’s therefore important to look more closely at the words’ meaning and function, rather than their pronunciation alone.

For example:

Loath is almost always followed by a phrase beginning with an infinitive (an uninflected verb preceded by to) that completes its meaning—this is known as an adjective complement. While loathe can also be followed by an infinitive phrase (functioning as a direct object), it doesn’t have to; anything functioning as a noun can be its object.

As a quick mnemonic trick, just remember that loathe functions as a verb, so it is spelled with an E at the end.