ag, adj. — Green’s Dictionary of Slang

ag adj.

[abbr. SE aggravated but note agg v.]

(US campus)

1. angry, annoyed, irritated, also as adv.

1997–2001		Online Sl. Dict. 🌐 ag adj 1. aggravated or upset. (‘She got all ag because I didn’t give her money back to her.’) Origin: first used in the early 1990’s. Note: diminutive form of ‘aggro’.
2018-20		T. Thorne (ed.) ‘Drill Slang Glossary’ at Forensic Linguistic Databank 🌐 Aggy – aggressive(ly).

2. crazy, fun.

1997–2000

College Sl. Research Project (Cal. State Poly. Uni., Pomona) 🌐 Ag (adj.) Crazy; fun. [University of San Diego, San Diego, CA] (primarily used by surfers).