(one's) best shot
The utmost of one's effort, ability, or determination spent attempting to do something. I gave writing my best shot, but I just don't think I can make a career out of it. That was our best shot—let's hope it was enough to fix things.
one's best shot
Fig. one's best attempt (at something). That was his best shot, but it wasn't good enough. I always try to give something my best shot.
one’s best shot
n. one’s best attempt (at something). That was his best shot, but it wasn’t good enough.