fruitless
adjective uk/ˈfruːt.ləs/ us/ˈfruːt.ləs/
无成果的；无效的
If an action or attempt to do something is fruitless, it is unsuccessful or produces nothing of value.
All diplomatic attempts at a peaceful solution to the crisis have been fruitless. 所有试图和平解决这场危机的外交努力都毫无成效。
Synonyms: futilevain
Opposite: fruitful