1) Cross off as a possibility 2) Dismiss from consideration 3) Eliminate 4) Eliminate as a possibility 5) Nix as a possibility 6) Prevent 7) Remove from consideration 8) Shut the door on 1) Removed from consideration 1) Excludes by decision 
Rule out: A term much used in medicine, meaning to eliminate or exclude something from consideration. The ACB (albumin cobalt binding) test helps rule out a heart attack in the differential diagnosis of severe chest pain.
[v] - include or exclude by determining judicially or in agreement with rules 2. [v] - dismiss from consideration
A possible cause for a patient's problem. Also called a differential diagnosis.