Answer: ack

AnswerCrossword Clue
ACKAerial defense, when doubled
ACKCry of surprise in the comics
ACKBill the Cat pronouncement, in the funnies
ACKCathy's cry
ACKCathy's comics cry
ACKComic strip exclamation
ACKRepeated, antiaircraft fire
ACKShort reply
ACKHalf an aerial defense
ACKBill the Cat's comment
ACKCry of horror, in the comics
ACKMachine gun sound
ACK'Oh, no!,' in comics
ACK"Egads!"
ACKWhen doubled, defensive fire
ACKCousin of "aargh!"
ACKRelative of "Oh, no!"
ACKWhen repeated, antiaircraft fire
ACKComics outburst
ACKBit of artillery fire
ACK... emma (A.M.)
ACKPip emma or ... emma (P. M. or A. M.).
ACK... emma (A. M.).
ACKAnswering letter: Abbr.
ACKLetter of reply: Abbr.
ACK... emma, A. M. in telephonese.
ACK... emma: A. M. in telephony.
ACKReport receipt of: Abbr.
ACK... emma (a.m.).
ACK... emma and pip emma.
ACKComment from Bill the Cat, in the comics
ACK... emma.
ACKRecognize: Abbr.
ACK... emma (A.M. in England)
ACK... emma (before noon)
ACK... emma (before noon, to British signalmen)
ACKPart of A.A. fire
ACK... emma (before noon in England)
ACKFlak sound
ACKHalf an antiaircraft weapon