frightfully

/ˈfraɪtfəli/
adverb
  1. Very; extremely (used for emphasis, often in a slightly old-fashioned or British way).
    • I'm frightfully sorry for being late to the party.
    • The weather was frightfully cold during our hike in the mountains.
    • She looked frightfully elegant in her new evening gown.
  2. In a way that causes fear or terror.
    • He screamed frightfully when the spider crawled onto his hand.
    • The old house creaked frightfully in the wind at night.
    • The storm howled frightfully, shaking the windows.
Antonyms
What does "frightfully" mean? | whatsthatwordmean | whatsthatwordmean