1
general::
Phrase(s): in vain
for no purpose; [done] as a failure. • They rushed her to the hospital, but they did it in vain. • We tried in vain to get her there on time.
McGrawhill's American Idioms And Phrasal Verbs
2
general::
To no avail, useless, as in All our work was in vain. [c. 1300] Also see TAKE SOMEONE'S NAME IN VAIN.
American Heritage Idioms