The most common and most likely answer to this crossword clue is the 5 letter word PANSY
I've seen this crossword clue in The Daily Telegraph
P
A
N
S
Y
Buddy explains!

The straight part
We know that "Violet" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case violet = pansy.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does PANSY mean?
PANSY noun- A cultivated flowering plant, derived by hybridization within species Viola tricolor.
- A deep purple colour, like that of the pansy.
- Any of various nymphalid butterflies of the genus Junonia. Also called arguses.
- A male homosexual, especially one who is effeminate.
- A timid, weak man or boy; a wuss.
- (usually with "around" or "about") To mess about; to fail to get things done.
- Wimpy; spineless; feeble.
- Of a deep purple colour, like that of the pansy.