Communist radical picked up as requested (2,5)
I believe the answer is:
to order
'as requested' is the definition.
(as in items made to order)
'communist radical picked up' is the wordplay.
'communist' becomes 'red' (red can informally mean communist).
'radical' becomes 'root' (synonyms).
'picked up' is a reversal indicator.
'red'+'root'='redroot'
'redroot' written backwards gives 'TO ORDER'.
(Other definitions for to order that I've seen before include "In fulfilment of an instruction" , "In accordance with specification" , "As specified" , "as required" .)