1) A feeble attempt to cover the complete emptiness of one's head.
2) A Moronic response to any question, statement or situation. Slightly less intellectual than, "Huh?" Prompted by exposure to anything one's stunted life experience has not prepared the Individual for.
EXCEPTION: Any Ordinary middle-aged parent may be reduced to "Hah?" by an encounter with their 12 to 17 year-old adolescent. Fathers are particularly vulnerable to this Syndrome while interacting with their Pubescent Daughters.
1) A very sexy young woman grinds her way across the room; all turned out, "Daddy-O, ummmm- I need you to take me to my birth control appointment." The Father looks up at his 13 year-old Daughter, and says, "Hah?"
2) SEXY BLONDE: "Joey, which do you like better, local Microbrew OR a nice dry Chardonnay?" JOEY: "Hah?"