The most common and most likely answer to this crossword clue is the 6 letter word SACRED
I've seen this crossword clue in The Guardian
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More clues leading to the result SACRED
- Holy ship’s company mostly in blue
- Holy wine by fire, mostly
- Holy Land area within borders of sand
- Holy, as reflected by almost all doctrine
- Holy scriptures are commonly read every day, first of all
- Consecrated area of land in outskirts of Stroud
- Catholic head of school with a set of beliefs exuding love
- Part of God’s acre duly consecrated
- Holy area in outskirts of Samarkand
- Holy bag the colour of blood
Buddy explains!

The straight part
We know that "Holy" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case holy = sacred.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 SACRED mean?
SACRED adjective- Characterized by solemn religious ceremony or religious use, especially, in a positive sense; consecrated, made holy.
- Religious; relating to religion, or to the services of religion; not secular
- Spiritual; concerned with metaphysics.
- Designated or exalted by a divine sanction; possessing the highest title to obedience, honor, reverence, or veneration; entitled to extreme reverence; venerable.
- Not to be profaned or violated; inviolable.
- (followed by the preposition "to") Consecrated; dedicated; devoted
- Solemnly devoted, in a bad sense, as to evil, vengeance, curse, or the like; accursed; baleful.
- To consecrate