Abstinent — muted in colour (5)

I believe the answer is:

sober

This clue is a double definition.

'abstinent' is the first definition.
(similar in meaning)

'muted in colour' is the second definition.
(I've seen this before)

(Other definitions for sober that I've seen before include "Snot drunk" , "Sedate and rational" , "Staid; clear-headed" , "Judge said to be so" , "Serious or solemn and not drunk" .)

I've seen this clue in The Guardian.

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