Discoloured is defined as something that has lost its original color or has changed to an undesirable hue. Some synonyms for this word include stained, tainted, faded, dulled, tarnished, and yellowed. When something is stained, it has been marked with a non-removable mark or discoloration. Tainted can refer to something that has been contaminated or defiled. Faded means that something has lost its brightness or intense color. Dulled implies that something has lost its shine or luster. Tarnished is used to describe something that has lost its original shine and is now dull or discolored. Yellowed describes something that has become yellow in color or has taken on an unsightly hue.