antiaircraft

nouns

artillery designed to shoot upward at airplanes
ack-ack, ack-ack gun, antiaircraft, antiaircraft gun, flack, flak, pom-pom

adjectives

designed for defense from a surface position against air attack
antiaircraft
is similar to
intended or appropriate for defending against or deterring aggression or attack
"defensive weapons"; "a defensive stance"
defensive