IPA: /ˈpɛrɪləsli/
KK: /ˈpɛrɪləsli/
In a way that involves a lot of danger or risk.
The climbers moved perilously close to the edge of the cliff.
Perilously → It is formed from "peril" (from Old French *peril*, meaning danger) and the suffix "-ously" (meaning in a manner characterized by). The word "perilously" means in a manner that is characterized by danger or risk.
Think of 'peril' as danger, and remember that 'perilously' describes doing something in a dangerous way.