not stand an earthly
To have no possible or feasible chance (of doing or accomplishing something). A truncated form of "not stand an earthly chance." Primarily heard in UK. He doesn't stand an earthly of winning, but I'm voting for him nonetheless. I knew I wouldn't stand an earthly of getting that promotion if I didn't make myself stand out in the company more.
not stand (or have) an earthly
have no chance at all. British informal