Corrosive substances are substances that can damage tissues when they come in contact with them. An example of a corrosive substance is the liquid, hydrochloric acid, an acid used in some toilet bowl cleaners. Corrosive is one of the five danger risks that a liquid can have, along with toxic, flammable, explosive, and biological hazard.
Corrosive substances are to be dealt with extreme precaution and care. They are extremely dangerous.