Short for Chinese Communist and sometimes Chinese Communications (military intel, not normal language), and also widely used in military terms to describe something Chinese such as a Type-56 assault rifle or a Chicom Bag and sometimes in general to things which pertain to asian communism. Chicom originated out of the Vietnam War and was first used as slang for tiny burlap bags or packets which usually contained Chinese, NVA, or Vietcong made communist propaganda as well as intel, ammo, food, medical supplies, etc.
Private Steve:"These chicom rations taste like rat shit..." Sargeant Wilko: "That chicom ration IS rat shit... your eating a can filled with it you moron!"
A brainwashed or stupid person who actually believes that Maoism, red fascism, and socialism with "Chinese" characteristics have something to do with communism. These people tend to be mindless conservative or China apologists.