IPA: /ˈɡriːsləs/
KK: /ˈɡrisləs/
Not having any grease or oil; clean and free from fatty substances.
The greaseless cooking method made the food healthier and less messy.
Greaseless → It is formed from "grease" (from Old English *grǣs*, meaning a fatty substance) and "-less" (meaning without). The word "greaseless" means without grease or free from grease.
Think of being 'without' ('-less') a 'fatty substance' ('grease') — that's why greaseless means free from grease.