In a way that causes worry, concern, or upset; in a manner that is disturbing or troubling.
Adverbial form of 'distressing' (present participle of 'distress' + '-ing'). The '-ly' suffix converts adjectives to adverbs. This is the most common '-ly' form in the distress family.
Speakers choose 'distressingly' over 'distressfully' because the '-ing' participle form feels more natural and modern in English than the older '-ful' adjective forms—it's a window into which word forms feel alive versus archaic.
Complete word intelligence in one call. Free tier — 50 lookups/day.