HMSS is an acronym that stands for "Her Majesty's Secret Service," a term often associated with the British intelligence agency known as MI6. Some synonyms for the acronym HMSS might include "British Intelligence," "Secret Intelligence Service," or simply "MI6." Other related terms that could be used as synonyms for HMSS might include "espionage," "intelligence gathering," "counter-intelligence," or "espionage operations." While these terms are not exact synonyms for the term "HMSS," they are all related to the concept of intelligence gathering and covert operations, which are commonly associated with MI6 and other intelligence agencies around the world.