'devoutly' originates from the Latin word 'devotus,' where 'de-' meant 'down' and 'votum' meant 'vow.'

'devotus' transformed into the Old French word 'devot,' and eventually became the modern English word 'devoutly' through Middle English.

Initially, it meant 'dedicated by a vow,' but over time it evolved into its current meaning of 'with deep religious feeling or commitment.'