The Collaborative International Dictionary of English v.0.48:
aggro \aggro\ n. 1. aggravation or aggression. [informal British usage] I skipped it because it was too much aggro [WordNet 1.5]WordNet (r) 3.0 (2006):
aggro n 1: (informal British usage) aggravation or aggression; "I skipped it because it was too much aggro"