In a manner that detracts from or reduces the value or respect of something; in a disparaging or diminishing way.
From 'derogate' + '-ly' adverbial suffix. Follows standard English adverb formation patterns to convert the verb into a manner adverb.
This is a precision adverb for a very specific communicative intent—to describe doing something while simultaneously reducing its importance. It's the kind of word diplomats might use when forced to acknowledge something they want to minimize.
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