GTL (jerseyan, n.)—the abbreviation for the guido way of life, which stands for gym, tanning, laundry.
So here are some—in both jerseyan and Italian slang—to get him, the rest of the cast, and viewers started.
1580s as a type of knitted cloth; 1842 as a breed of cattle; both from Jersey, one of the Channel Islands. Its name is said to be a corruption of Latin Caesarea, the Roman name for the island (or another near it), influenced by Old English ey "island;" but perhaps rather a Viking name (perhaps meaning "Geirr's island"). The meaning "woolen knitted close-fitting tunic," especially one worn during sporting events, is from 1836.