noun
thick Osaka dialect (as supposedly spoken by Hanshin Tigers fans)
Slang, jocular term. Refers to the exaggerated, stereotypical Osaka-ben associated with passionate Hanshin Tigers supporters. Often used humorously or self-deprecatingly.
彼は関西出身じゃないのに、野球の話になると急に猛虎弁になる。
He's not from Kansai, but when the topic turns to baseball, he suddenly starts speaking in thick Tigers-fan Osaka dialect.
Compound of 猛虎 (もうこ, 'fierce tiger', referring to the Hanshin Tigers baseball team) and 弁 (べん, 'dialect'). The exact origin is uncertain, but it likely arose from the stereotype of passionate Tigers fans speaking in a rough, emphatic Osaka dialect.