The most common and most likely answer to this crossword clue is the 4 letter word PINK
I've seen this crossword clue in The Guardian
P
I
N
K
More clues leading to the result PINK
Buddy explains!

The straight part
We know that "Colour" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case colour = pink.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 PINK mean?
PINK noun- The common minnow, Phoxinus phoxinus.
- A young Atlantic salmon, Salmo salar, before it becomes a smolt; a parr.
- A narrow boat.
- A stab.
- To decorate a piece of clothing or fabric by adding holes or by scalloping the fringe.
- To prick with a sword.
- To wound by irony, criticism, or ridicule.
- To choose; to cull; to pick out.
- Any of various flowers in the genus Dianthus, sometimes called carnations.
- A perfect example; excellence, perfection; the embodiment of some quality.
- The colour of this flower, between red and white; pale red.
- Hunting pink; scarlet, as worn by hunters.
- One of the colour balls used in snooker, with a value of 6 points.
- An unlettered and uncultured, but relatively prosperous, member of the middle classes; compare Babbitt, bourgeoisie.
- The vagina or vulva.
- To become pink in color, to redden.
- To turn (something) pink.
- To turn (a topaz or other gemstone) pink by the application of heat.
- Having a colour between red and white; pale red.
- Of a fox-hunter's jacket: scarlet.
- Having conjunctivitis.
- By comparison to red (communist), describing someone who sympathizes with the ideals of communism without actually being a Russian-style communist: a pinko.
- Relating to women or girls.
- Relating to homosexuals as a group within society.
- A socialist who is not wholly communist.
- Of a motor car, to emit a high "pinking" noise, usually as a result of ill-set ignition timing for the fuel used (in a spark ignition engine).
- Of a musical instrument, to sound a very high-pitched, short note.
- To wink; to blink.
- Half-shut; winking.
- Any of various lake pigments or dyes in yellow, yellowish green, or brown shades made with plant coloring and a metallic oxide base.