Unnervingly means in a way that quietly takes away your confidence. Unnervingly calm.
It describes an effect on the observer rather than any intention. Something unnervingly accurate is more disturbing than something merely strange.
1adverbunnervinglyIn a way that quietly takes away your confidence.
“The house was unnervingly quiet for a Saturday.”
unnervingly is a manner.
From unnerving + -ly.
Etymology from Wiktionary, CC BY-SA