Flier's rôle, swinging up with lack of effort, say? (7)
I believe the answer is:
trapeze
'flier's role swinging' is the definition.
I know that 'swinging' relates to this answer.
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for trapeze that I've seen before include "Where swingers swing" , "Circus bar on ropes" , "Swing-like apparatus" , "What the daring young man in the circus flies on" , "Flying circus apparatus?" .)