chaack [Imitative.] The cry of the jackdaw. 1906Westm.Gaz. 9 June 13/2 With a little flutter of the wing and a cheery ‘Chaack!’ he hopped off one head on to another.1907Ibid. 19 Oct. 16/1 The cheering ‘cha-ack’ of the jackdaw is everywhere in the air.