It’s a verbal invitation to have your throat punched for being a smug, dismissive bastard.
Since this isn’t really a Cafe Society question, I’m moving this to General Questions.
Yep, “Hungry Hungry Homer,” Season 12, episode 15.
You can view the episode here. The “Meh” scene is in the first minute after the opening credits.
We’ve had several threads on this, however I can’t seem to find the truly great thread delineating the difference between “eh” “meh” and “feh”- I printed it out ages ago for a coworker who just wasn’t getting the subtle differences.
More specifically it’s a dismissive verbal shrug: “Whatever, I don’t care, drop it.” There’s also “enh”, which is pronounced more nasally and without the leading ‘m’. This is a more non-committal: “Whatever, I suppose so, it’s all the same to me.”