。
I'm what the world would call an idiot.
Literal
I [topic-は] society [at-で] say idiot [copula-です].
世間で言う ('what society/the world calls') frames the self-deprecation as an objective social assessment. アホ (fool, idiot) is historically Kansai dialect but now widely understood nationwide, though it retains a slightly different nuance from バカ — more good-natured, less harsh. The polite です after a blunt self-insult creates a deadpan comic contrast.