IPA: /əˌpɒkəˈlɪptɪkli/
KK: /əˌpɑː.kəˈlɪp.tɪ.kli/
In a way that suggests a future disaster or great destruction.
The world was changing apocalyptically, with signs of chaos everywhere.
Apocalyptically → It is formed from "apocalypse" (from Greek "apokalypsis", meaning revelation or disclosure) and the suffix "-ally" (meaning in a manner relating to). The word "apocalyptically" refers to something that relates to or resembles a revelation, often in a dramatic or catastrophic sense.
Think of 'apocalypse' as a 'revelation' and remember that 'apocalyptically' means in a manner that relates to such a dramatic revelation.