"Anti-art" art movement (4)
I believe the answer is:
'anti-art art movement' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for dada that I've seen before include "Precursor of surrealism" , "Early 20th-century avant-garde art movement" , "Art movement exemplified by Man Ray and Marcel Duchamp" , "form of art" , "Early 20th-century arts movement, emphasizing the absurd" .)