a police patrol car—UK, 1959—originally any of the special crime police patrol cars used in Lancashire—from the radio call-sign ‘Z’ allotted to such cars—popularised by the British television series ‘Z Cars’ (1962-78)
Australia, 1932—also ‘Flemington confetti’ (1933) and ‘farmyard confetti’ (1967)—bullshit (i.e., nonsense, rubbish)—also occasionally used literally in the sense of faeces
Yorkshire & Lancashire (northern England), first half of the 19th century—the evening of 30th April (May Eve), on which people traditionally indulged in mischievous pranks
Australia, 1950—UK, 1962—derogatory and offensive: a middle-aged or elderly woman, especially one who is unattractive or unfeminine—refers to ‘boiler’, i.e., a tough old chicken for cooking by boiling
the imaginary vehicle supposed to take people to the mental asylum—Australia (1869), New Zealand (1884)—the reason the colour green was chosen is unknown
also ‘like a lily on a dirt-tin’ and variants—something or somebody that is incongruous or conspicuous—UK, 1934, but chiefly Australian (from 1948 onwards)
a humorous redefinition of an existing word or phrase, presented as a dictionary definition—USA, 1910—a blend of the adjective ‘daffy’ and of the noun ‘definition’