Clue: Dadaist back cycling (5)
Answer: ERNST
Explanation: Definition: Dadaist
(st)**ERN**(**ST**) ("back" *cycling*) *The best way I can think of to descibe the "cycling" element is to think of a wheel with the letters of STERN in order around the edge, and with S at the top. If you turn (cyle) it two-fifths of the way round anti-clockwise, the E would now be at the top and would spell out ERNST* 
*Max Ernst was one of the principal artists in the Dada movement.