Fig. a final effort; the last possible attempt. (*Typically: be ~; have ~; make ~.) I made one last-ditch effort to get her to stay.It was a last-ditch effort. I didn't expect it to work.
A desperate final attempt, as in We're making a last-ditch effort to finish on time. This expression alludes to the military sense of last ditch, "the last line of defense." Its figurative use dates from the early 1800s.