An esoteric reading
The early-twentieth-century writer George Carey, in his 1920 book God-Man: The Word Made Flesh, connected the English word "sin" to Schin, the twenty-first letter of the Hebrew alphabet, glossing it as a falling short of completeness, understanding, or wisdom. In this same symbolic vocabulary, the Tarot's "Blind Fool" is read as an image of that same lack of wisdom, and the phrase "brought forth in iniquity" is treated as another way of saying "born in sin."
Carey also linked the word, in this same interpretive vein, to Sin, a name used in the ancient Near East for a moon deity — noting that the moon "gives light only part of the time." This is best understood as one esoteric author's symbolic association between similar-sounding words across languages, not as an established etymology of the English word "sin."