V-ERG
(使)变色;(使)褪色
If something discolours or if it is discoloured by something else, its original colour changes, so that it looks unattractive.
例句
A tooth which has been hit hard may discolour...
受过重击的牙齿可能会变色。
Some oil had seeped out, discolouring the grass.
有些油渗出来了，把草地染得变了颜色。