alarmingly

1 of 1adverb

/əˈlɑrmɪŋli/

1

in a manner that causes sudden concern or fear

The lights flickered alarmingly before the power cut out.
The patient began breathing alarmingly fast after the injection.
The crowd grew alarmingly quiet as the news spread.
The engine began to rattle alarmingly just before takeoff.
The building shook alarmingly during the minor quake.

Synonyms:

worryingly disturbingly