Penalised, we hear, for discovery (4)
I believe the answer is:
find
'discovery' is the definition.
('find' can be a synonym of 'discovery')
'penalised we hear' is the wordplay.
'penalised' becomes 'fined' ('fined' can be a synonym of 'penalized').
'we hear' shows a homophone (sound like).
'fined' sounds like 'FIND'.
'for' acts as a link.
(Other definitions for find that I've seen before include "Discover by chance" , "Encounter, locate" , "Locate or discover" , "Acquisition" , "Come across" .)