frighteningly

/ˈfraɪtənɪŋli/
adverb
  1. In a way that causes fear or is very alarming.
    • The car swerved frighteningly close to the edge of the cliff.
    • The storm approached frighteningly fast, forcing everyone to take shelter.
    • Her scream was frighteningly loud in the silent house.
  2. Used to emphasize that something is extremely or surprisingly great in degree, often in a negative or shocking way.
    • He was frighteningly good at chess, beating every opponent in minutes.
    • The cost of the repairs was frighteningly high.
    • The amount of plastic in the ocean is frighteningly large.
Antonyms
What does "frighteningly" mean? | whatsthatwordmean | whatsthatwordmean