What is "tgt"

TGT may stand for Trained Graduate Teracher:

TGT was a supergroup that consisted of R&B singers Tyrese (Tyrese Gibson), Ginuwine (Elgin Baylor Lumpkin) and Tank (Durrell Babbs). TGT is named after the first letter of each of the trio's stage names (T for Twat, G for Gimp, and T for Tit). The three are close friends and Tyrese was best man at Ginuwine's wedding, but TGT represented their first collaboration. Despite being together as a super group since its formation in 2007, it released its debut album only in August 2013 titled Three Kings on Atlantic Records.