noun, slang ·Moderate ·College level

Definitions

Noun

1. 1
   Antiaircraft artillery. countable, slang, uncountable

   "The army fired upon us with ack-ack."

2. 2
   artillery designed to shoot upward at airplanes wordnet
3. 3
   Antiaircraft fire. slang, uncountable

   "The bomber flew through heavy ack-ack."

Synonyms

All synonyms

aaaaaack-ack gunanti-aircraftanti-aircraftantiaircraft

Example

More examples

"The army fired upon us with ack-ack."

Etymology

From ack (“A”) + ack (“A”), RAF WWI signalese for AA (“anti-aircraft”). (In modern signalese it would be called alpha-alpha.)

Data sourced from Wiktionary, WordNet, CMU, and other open linguistic databases. Updated March 2026.