Sanctimonious

google

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early 17th century (in the sense ‘holy in character’): from Latin sanctimonia ‘sanctity’ (from sanctus ‘holy’) + -ous.

wiktionary

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sanctimony +‎  -ous

etymonline

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sanctimonious (adj.)

c. 1600 (in "Measure for Measure," with the disparaging sense "making a show of sanctity, affecting an appearance of holiness"), from sanctimony + -ous. The un-ironic, literal sense is about as old in English and was used occasionally from c. 1600 to c. 1800. Related: Sanctimoniously; sanctimoniousness.