Mar (5)
'mar' is the definition.
(tainting is a kind of marring)
This is all the clue.
(Other definitions for taint that I've seen before include "Defect - contamination" , "Corrupt" , "Blemish" , "(Trace of) corruption" , "It isn't commonly" .)
'mar' is the definition.
(synonyms)
This is all the clue.
(Other definitions for spoil that I've seen before include "Diminish or destroy the value or quality" , "Cook" , "Harm or destroy" , "Destroy or ruin" , "Waste from mining; mar" .)
'mar' is the definition.
(defacing is a kind of marring)
This is all the clue.
(Other definitions for deface that I've seen before include "ruin" , "Spoil or damage the surface of" , "Wantonly spoil the look of" , "Mar or spoil the appearance of" , "Deliberately spoil the appearance of something" .)
'mar' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for ruin that I've seen before include "Reduce to bankruptcy" , "Destroy completely" , "Utter destruction or downfall" , "Complete collapse or destruction" , "Wrecked building" .)