Dissonant surfer treated a thick prospect losing foot (10)
I believe the answer is:
hacktivist
'prospect losing foot' is the definition.
The definition suggests a singular noun which matches the answer.
'dissonant surfer treated a thick' is the wordplay.
I cannot quite see how this works, but
'a' is present in the answer.
an anagram of 'thick' is 'hckti' which is present in the remaining letters.
This explanation may well be incorrect...
Can you help me to learn more?
(Another definition for hacktivist that I've seen is " Subversive in the IT dept".)