Trapped pioneer in demand (6)
I believe the answer is:
netted
'trapped' is the definition.
(I've seen this before)
'pioneer in demand' is the wordplay.
'pioneer' becomes 'tt' (I am not sure about this - if you are sure you should believe this answer much more).
'in' is an insertion indicator.
'demand' becomes 'need' (synonyms).
'tt' inserted inside 'need' is 'NETTED'.
Can you help me to learn more?
(Other definitions for netted that I've seen before include "Caught fish, perhaps, and made clear profit" , "Gained as profit" , "Captured" , "Trapped" , "As a whole" .)