In a manner that lacks devoutness; without sincerity, reverence, or religious dedication.
From 'devoutless' (adjective lacking devoutness) plus '-ly' adverb suffix. Creates the adverbial form of a negative adjective, layering suffixes: devout + -less + -ly.
Multi-suffix stacking like 'devoutlessly' (devout-less-ly) is grammatically valid but sounds awkward, which is why such words are rare—English speakers find it harder to process three suffix layers than two.
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