Hooah

Hooah is military slang "referring to or meaning anything and everything except no" used by soldiers in the U.S. Army and airmen of the U.S. Air Force.

Possible meanings
Some popular usages of hooah include:
 * HUA means: "Heard, understood, and acknowledged"   (backronym as "HUA")
 * What to say when at a loss for words
 * "Good copy"
 * "Roger," "solid copy," "good," "great," "message received," "understood," "acknowledged"
 * "Glad to meet you," "welcome"
 * "All right!"
 * "Thank you"
 * "Eh?"
 * "You've taken the correct action"
 * "You're wrong, but you outrank me."
 * "Outstanding!"
 * "That's cool" or "that's OK." As in, "That's hooah."
 * To motivate another soldier.
 * Did not hear what was said, but not going to ask to repeat.
 * Anything and everything except "no."

Hooah can also:
 * be used as a call and response cheer, with one soldier exclaiming, "hooah!," and other soldiers responding in like.
 * be uttered at random and in a group in order to boost morale. One or a few soldiers will begin chanting "hooah!," and then others join in.
 * be used as a sarcastic remark for something specific to the Army. Sometimes used sarcastically. As in, "This detail is about as hoo-ah as it gets."
 * be used to describe a highly motivated individual. As in, "Greenfield has been extremely Hoo-ah lately."
 * be used to assert one's identity as a member of the Army (particularly in the midst of personnel from sister services)

Overuse
While used in Hollywood and in common usage among upper ranks in an effort to raise morale, many lower enlisted find its use to be irritating, especially when it comes from soldiers they perceive as sycophantic towards the chain of command or the armed services in general. In the Canadian armed forces, its overuse may incite ill will towards the user, who is often perceived not taking the job seriously (treating the job like a cliched film), or as unpatriotic due to the distinctly American flavour the term has come to embody thanks to American pop culture.