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Douglas Harper's Etymology Dictionary
hamartiology

"that part of theology which deals with sin," 1875, from Greek hamartia "sin" (see hamartia) + -ology.

Wiktionary
hamartiology

n. The theology of sin.

Wikipedia
Hamartiology

Hamartiology (from Greek: ἁμαρτία, hamartia, "missing the mark, error" and -λογια, - logia, "study"), a branch of Christian theology, studies sin.