There are many synonyms for the word "stonewaller", which refers to someone who refuses to provide information or cooperate with others. Some common synonyms include "obstructer", "evader", "barrier", "resister", and "holdout". Other possible synonyms include "silent partner", "secretive individual", "uncommunicative person", "stubborn opponent", and "closed-mouth adversary". Whatever term is used, the underlying behavior is the same: an unwillingness or inability to share information or work collaboratively with others. This can lead to frustration, confusion, or even outright conflict in a wide range of social, professional, and personal contexts.