Contaminates (6)
I believe the answer is:
taints
'contaminates' is the definition.
(tainting is a kind of contaminating)
This is all the clue.
(Other definitions for taints that I've seen before include "Traces of bad quality in titans" , "Contaminates" , "Traces of decay in Titans" , "Flaws in titans" , "Pollutes" .)