acrimony

This term describes a sharp, stinging quality of interaction, often manifesting as caustic speech or deep-seated resentment. It suggests a level of hostility that is not merely an argument, but a corrosive emotional state that poisons a relationship or a professional environment. As an uncountable noun, acrimony does not have a plural form and cannot be counted with numbers. To quantify it, one must use partitive phrases such as a degree of acrimony or a sense of acrimony.