IPA: /ˈɔɪli/
KK: /ˈɔɪli/
Having a lot of oil or grease; slippery and shiny.
The oily surface of the pan made it difficult to cook the eggs without them sticking.
Oily → It is formed from "oil" (from Old French *oile*, meaning a fatty substance) and the suffix "-y" (meaning characterized by). The word "oily" describes something that is characterized by or contains oil.
Think of something that is 'characterized by' ('-y') a 'fatty substance' ('oil') — that's why oily means something that has oil in it.