It is an inspirational phrase which garners a callback that is used to show an expression of gratitude, agreement, and approval. It is used most commonly in an inspirational speech setting in which a motivational speaker will say this phrase to whatever crowd he/she is speaking to and they are obligated by law to respond with HUN-DO simultaneously. Per tradition they shall of course accompany the Hun-do with the appropriate/respectful hand motion (where you put your pointer finger down and go on a little rollercoaster with said finger before finally ending with the finger pointing up). If the crowd happens to be seated, then they shall rise at once to chant the great words of HUN-DO. The speaker uses this word to garner support for whatever they happen to be preaching. This call and response originated from the brain of Noah Weinberg while he was dreaming. He has said his “all time life goal is to have 50,000 people respond to Hun-What? with an absolutely fantastic rendition of the HUN-DO.”
Inspirational speaker: It only takes one moment to say no, to say never again, never again will I settle. Never again will I accept anything but first place
Crowd: *cheers and claps*
Inspirational speaker: Hun-What?
Crowd: *rises to their feet* HUNDO
Crowd: *cheers and claps*
Inspirational speaker: Hun-What?
Crowd: *rises to their feet* HUNDO
by BHPH November 30, 2018
Get the Hun-What?mug. by nylad November 3, 2015
Get the stun hunmug. by Jennifer Spur September 7, 2006
Get the Hun-Bunmug. "I met this little hun-dog last night!"
Also used as "Hundos" for a multitude of "hun-dogs"
"Dang, look at those hundos"
Also used as "Hundos" for a multitude of "hun-dogs"
"Dang, look at those hundos"
by the_diabolical_dr.please December 27, 2009
Get the hun-dogmug. by YOUNG TUCK July 15, 2014
Get the 21 hunnedmug. 
A complete beast that all but conquered Rome. Widely known as the founder of Hungary. Also said to be hung like an Italian blue whale.
by nipmynuts December 25, 2010
Get the Attila the Hunmug.