IPA: /həˈrɛndəsli/
KK: /hɔːˈrɛndəsli/
In a way that is extremely bad or unpleasant.
The movie was horrendously boring, and I couldn't stay awake.
Horrendously → It is formed from "horrendus" (from Latin, meaning dreadful or terrible) and the suffix "-ly" (meaning in a manner of). The word "horrendously" means in a manner that is dreadful or terrible.
Think of something that is 'dreadful' ('horrendus') and remember that 'horrendously' describes doing something in a dreadful way.
No commonly confused words.