Answer: ackack

AnswerCrossword Clue
ACKACK

Antiaircraft fire

ACKACK

Antiaircraft fire, informally

ACKACK

WWII defense

ACKACK
Anti-aircraft fire.
ACKACK
Sound of gunfire.
ACKACKAir-raid gun
ACKACKAir-defense fire
ACKACKKind of gun
ACKACKGun aimed at a bomber
ACKACKAnti-aircraft gun's onomatopoeic nickname
ACKACKWWII gun