IPA: /ˈpɛstɪləntli/
KK: /ˈpɛstɪləntli/
In a way that causes or relates to disease or harm; destructively or mischievously.
The pests spread the disease pestilently, affecting the entire crop.
Pestilently → It is formed from "pestilent" (from Latin "pestilentem", meaning causing plague or disease) and the suffix "-ly" (meaning in a manner of). The word "pestilently" means in a manner that causes disease or plague.
Think of something that causes disease ('pestilent') and remember that 'pestilently' describes how it spreads or acts in a harmful way.