The phrase "be corrosive" refers to the ability of a substance or material to gradually wear away, damage, or destroy another substance or material. Some synonyms for this phrase include "erode," "deteriorate," "wear down," "decay," and "eat away." These words all describe the gradual breakdown of a substance or material due to exposure to a corrosive agent like acid, salt, or moisture. Other synonyms for "be corrosive" include "corrode," "rust," "oxidize," and "tarnish." These words are often used to describe the chemical processes that occur when metals and alloys come into contact with oxygen or other corrosive agents, leading to rust or discoloration.