Countdown supporter's vigorous handclap taking in the final vowel (6,3)
I believe the answer is:
launch pad
'countdown' is the definition.
Although both the answer and definition are singular nouns, I can't see how they can define each other.
'supporter's vigorous handclap taking in the final vowel' is the wordplay.
I cannot quite see how this works, but
'vowel' could be 'u' and 'u' is located in the answer.
an anagram of 'handclap' is 'lanchpad' which is present in the left over letters.
No letters remain.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for launch pad that I've seen before include "Good place to begin" , "Structure on which a rocket sits" , "Rocket's starting point" , "platform" , "explorer's starting place" .)