Violet almost changed colour (5)
I believe the answer is:
olive
'colour' is the definition.
(olive is a kind of colour)
'violet almost changed' is the wordplay.
'almost' means to remove the last letter (almost the whole word is kept).
'changed' indicates an anagram.
'violet' with its final letter removed is 'viole'.
'viole' anagrammed gives 'OLIVE'.
(Other definitions for olive that I've seen before include "Small green tree-fruit, nice in martini" , "One [TYPE OF TREE] is from the Mediterranean" , "Oily stone fruit" , "Girl's name - colour" , "I love this fruit" .)