The most common and most likely answer to this crossword clue is the 5 letter word PURER
P
U
R
E
R
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The straight part
We know that "having less impurity" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case having less impurity = purer.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 PURER mean?
PURER adjective- Free of flaws or imperfections; unsullied.
- Free of foreign material or pollutants.
- Free of immoral behavior or qualities; clean.
- Mere; that and that only.
- (of a branch of science) Done for its own sake instead of serving another branch of science.
- Of a single, simple sound or tone; said of some vowels and the unaspirated consonants.
- (of sound) Without harmonics or overtones; not harsh or discordant.