No trouble dropping base in concrete (7)
I believe the answer is:
refusal
'no' is the definition.
(refusing is saying no)
I don't understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for refusal that I've seen before include "Instance of a horse not jumping" , "opportunity to accept or decline" , "Repudiation" , "Chance to decline" , "Non-acceptance" .)