Both Uses

loathe
in
The Screwtape Letters
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He really does want to fill the universe with a lot of loathsome little replicas of Himself-creatures, whose life, on its miniature scale, will be qualitatively like His own, not because He has absorbed them but because their wills freely conform to His.†
Chpt 8 *

loathsome = disgusting or very bad
The danger of inducing cowardice in our patients, therefore, is lest we produce real self-knowledge and self-loathing with consequent repentance and humility.†
Chpt 29

loathing = disgust or intense dislike

Definitions:

(1) (loathe)
hate, detest, or intensely dislike

Word Confusion: Do not confuse loathe with loath which sounds very similar or the same. Loathe is a verb while loath is an adjective describing "reluctance or unwillingness to do something." Note that loathing and loathsome are forms of the verb loathe even though both word forms lack the "e". Occasionally, you will see loath spelled as loathe even in a published book, but it is rare enough that it is generally considered an error rather than a non-standard spelling.
(2) (meaning too rare to warrant focus)