( BrE ) ( NAmE dis·color ) / dɪsˈkʌlə(r); NAmE / verb
to change colour, or to make the colour of sth change, in a way that makes it look less attractive :
[ v ]
Plastic tends to discolour with age.
[ vn ]
The pipes were beginning to rust, discolouring the water.
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WORD ORIGIN
late Middle English : from Old French descolorer or medieval Latin discolorare , from des- , dis- (expressing reversal) + Latin colorare to colour.