Pressure to get assistance rewarded (4)
I believe the answer is:
paid
'rewarded' is the definition.
(I've seen this in another clue)
'pressure to get assistance' is the wordplay.
'pressure' becomes 'p' (scientific abbreviation).
'to get' says to put letters next to each other.
'assistance' becomes 'aid' (synonyms).
'p'+'aid'='PAID'
(Other definitions for paid that I've seen before include "Hired" , "Trite phrase" , "Compensated" , "Aggressive, rowdy" , "Forked out" .)