ground-based anti-aircraft guns firing explosive shells(from 1938; synonyms: ack-ack, AAA, triple-A • […] to consider whether the city was in February 1945 an undefended city within the meaning of the 1907 Hague Convention, it will be necessary to examine the establishment and subsequent total dispersal of the city's flak batteries, before the date of the triple blow.wiktionary.org • He was promoted to general of flak artillery on March 1, 1945, and ended the war as the general of the flak arm at OKL, the High Command of the Luftwaffe.); anti-aircraft shell fire(from 1940; Synonym: ack-ack • At 1057 we were just over the islands and at 1100 the tail gunner reported flak at six o'clock, below.wiktionary.org • I could hear the fragments from the flak shells hitting the plane like someone throwing rocks at it.)
adverse criticism(from 1963 • Alex McLeish, perhaps mindful of the flak he has been taking from sections of the Villa support for a perceived negative style of play, handed starts to wingers Charles N'Zogbia and Albrighton.wiktionary.org • Raiders [of the Lost Ark] may also get flak for not being as cuddly-lovable as Star Wars, or for using those old reliables – the Nazis – as villains, or for dazzling the audience with an almost brazen self-confidence.)
a public-relations spokesperson(AIM head, Reed Irvine's diatribes are frequently published, and right-wing network flaks who regularly assail the “liberal media,” such as Michael Ledeen, are given Op-ed column space, sympathetic reviews, and a regular place on talk shows as experts.wiktionary.org)
wiktionary.org • He was promoted to general of flak artillery on March 1, 1945, and ended the war as the general of the flak arm at OKL, the High Command of the Luftwaffe.); anti-aircraft shell fire (from 1940; Synonym: ack-ack • At 1057 we were just over the islands and at 1100 the tail gunner reported flak at six o'clock, below. 