The most common and most likely answer to this crossword clue is the 8 letter word TONELESS
T
O
N
E
L
E
S
S
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The straight part
We know that "Lacking shade" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case lacking shade = toneless.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 TONELESS mean?
TONELESS adjective- Lacking tone or expression.
- Lacking vitality; listless.
- Lacking tone or pitch, have the neutral tone.