From WordNet (r) 3.0 (2006):
flak
n 1: a slick spokesperson who can turn any criticism to the
advantage of their employer [syn: flak catcher, flak,
flack catcher, flack]
2: intense adverse criticism; "Clinton directed his fire at the
Republican Party"; "the government has come under attack";
"don't give me any flak" [syn: fire, attack, flak,
flack, blast]
3: artillery designed to shoot upward at airplanes [syn:
antiaircraft, antiaircraft gun, flak, flack, pom-
pom, ack-ack, ack-ack gun]