Onomatopoeia that evokes the musical flourish that accompanies dramatic climaxes in movies and theatre performances. Used to express an emotional reaction to a sudden change of circumstances or something brought up in conversation, usually surprise or trepidation.
Person A: "The boss wants me to run the department while he's away on holiday."
Person B: "Duh nah nah nah!"
Person A: "I have to get back for an exam tomorrow but they just cancelled my flight!"
Person B: "Duh nah nah nah!"
Person B: "Duh nah nah nah!"
Person A: "I have to get back for an exam tomorrow but they just cancelled my flight!"
Person B: "Duh nah nah nah!"
by ChenBL December 27, 2020
Get the duh nah nah nahmug. Maya- you going to the store? Kayla- nah
by erhshs January 3, 2022
Get the nahmug. 
Where you don’t have no hot girl summer and you being good and ain’t no bitch ass guys tryna hit on you cause big jon gon whoop they ass
by Big jon Jon May 24, 2021
Get the Hell nah summermug.