Hooah (hü-ä or who-ah) is a U.S. Army slang term. It is use by US Army soldiers "Referring to or meaning anything and everything except no". It can also be a type of battle cry. The word's etymology is unclear, but one possible origin is that it is based on the acronym HUA, meaning "heard, understood, acknowledged". A joking etymology for this is also "Head Up Ass" so that Hua can have a double meaning, either a motivational one ("Hua, Sir, we'll take that hill") or else when told something that one couldn't possibly believe, they answer sarcastically with "Hua", knowing the other derivation.