in vain
Without effect; without getting the desired result; without success.
The drowning man called in vain for help.
To cry over spilled milk is to cry in vain.
All the doctors’ efforts to save the injured woman were in vain. She was declared dead three hours after being admitted to the hospital.
We tried in vain to reach you last night. Is your phone out of order?
Used as part of idiom take one's name in vain.
Thou shalt not take the name of the Lord thy God in vain.
Who’s that takes my name in vain?
take one's name in vain
To call upon (God) as a witness to your truth or honesty when you are lying; swear by (God) untruthfully.
You shall not take the name of the Lord your God in vain.
To talk about a person or mention his name.
"Did I hear someone taking my name in vain?" asked Bill as he joined his friends.