There are a plethora of antonyms for the word "MOD POWER SYST," but some of the most common words that are opposite to it include Vintage, Classic, Obsolete, Outdated, and Retro. These words depict the opposite of contemporary or modern power systems, which is what "MOD POWER SYST" stands for. While "Mod Power Syst" refers to the latest, most advanced, and updated systems of power generation and distribution, the antonyms show that some people still prefer the old, traditional, or outdated systems of power. Furthermore, it's essential to understand that some antonyms may carry negative connotations, while others may not. Therefore, a thorough analysis of the context and tone is required to determine the right antonym to use.