Relinquish flutter by phone (5)
I believe the answer is:
waive
'relinquish' is the definition.
(synonyms)
I cannot understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for waive that I've seen before include "Refrain from insisting on right or privilege" , "Don't insist on" , "Dispense with, forgo" , "Surrender" , "Not insist on (claim)" .)