From China Digital Space
土共 (Tǔgòng): TG (Earthy Communists)
The Chinese Communist Party. The first character, 土 tǔ, can be a noun meaning "earth" or "soil," or an adjective meaning "earthy," "unrefined," or "uncouth."
There is some disagreement about the origin of this term. Some say that TG derives from "Earthy Eighth Route" (土八路 Tǔ Bālù), a nickname for the Chinese communist military brigade during World War II known as the Eighth Route Army. Others believe TG was coined by Chiang Kai-shek to refer to the Chinese Communist Party (CCP) after he and the Nationalists fled to Taiwan. Still others say the term was invented in Hong Kong in the 1990s to disparagingly refer to the CCP.
@rifle76: To eat TG's food and oppose TG is disloyalty; to be a Chinese person and hold out the TG's rice bowl is an injustice. (April 8, 2015)
The letters "TG" may also stand for "celestial country" (天国 tiānguó), "corrupt official" (贪官 tānguān), or the English word "transgender."