Bias seems to corrupt missions (9)
I believe the answer is:
embassies
'missions' is the definition.
(I've seen this before)
'bias seems to corrupt' is the wordplay.
'to corrupt' indicates anagramming the letters (a corrupted form).
'bias'+'seems'='biasseems'
'biasseems' is an anagram of 'EMBASSIES'.
(Other definitions for embassies that I've seen before include "More than one mission" , "Missions" , "foreign delegations" , "Diplomatic buildings" , "Official residences of ambassadors" .)