goalpost

noun3

1. •
   One of the two vertical side poles of a goal.
2. •
   The tall Y-shaped upright, now usually of fiberglass, at either end of the playing field, through which a football must go in order for a field goal to be scored. (They were originally H-shaped, with one wooden post on either side.)
3. •
   A rule or target that is "moved" (changed) unfairly; see move the goalposts.

   • […] whatever you eat, how much you drink, you know the goalposts keep moving all the time, and it's difficult to be sure that, but I don't think it's harmful, not the amount I drink. — 2012