Answer:

wha

AnswerCrossword Clue
WHA"... happened?" ("A Mighty Wind" catchphrase)
WHA"... happened?" (Fred Willard's catchphrase in "A Mighty Wind")
WHA"Huh?"
WHABurns' "Scots, .. Hae"
WHA1970s NHL rival
WHA".. hoppen?"
WHACafe ...? (historic Greenwich Village nightclub)
WHAGroggy person's inquiry
WHA"Huh!?"
WHA"... hoppen?"
WHANHL rival, 1972-1979
WHA"Hunh?"
WHA".. hoppen?" (dazed one's query)
WHAWho: Scot.
WHAWord for Robert Burns.
WHA"Scots ... hae . . . "
WHAContemporary of T.S.E.
WHAFormer N.H.L. rival
WHAHouston Aeros' org.
WHA"... hoppen?!"
WHA"Huh ...?!"
WHAInquiry made while half awake, maybe
WHAAstonished query
WHA"Eh?"
WHAFormer NHL rival
WHAQuestion asked by one with a stuffy nose?
WHASleepy inquiry
WHAQuestion of perplexion
WHAQuestion asked with an open mouth