IPA: /ˈfruːtləs/
KK: /ˈfrutləs/
Not producing any useful results or success; unproductive.
After many fruitless attempts to fix the car, we decided to call a mechanic.
Fruitless → It is formed from "fruit" (from Old French *fruit*, meaning the product of plants) and "-less" (meaning without). The word "fruitless" means without fruit or without results.
Think of something that is 'without' ('-less') the 'product' ('fruit') of effort — that's why fruitless means not yielding any results.