The most common and most likely answer to this crossword clue is the 4 letter word HOLY
I've seen this crossword clue in The Guardian
H
O
L
Y
More clues leading to the result HOLY
- On the radio totally divine
- Following a religion, entirely on the radio
- Religious theory regularly baffles novice
- Devoted to God completely, by the sound of it
- Horribly heartless, yet pure in heart
- Edges of halo likely reflecting sainthood
- Said to be completely perfect
- Bush left out
- Divine note taken from sermon
- Very good and completely audible?
Buddy explains!

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 HOLY mean?
HOLY noun- A thing that is extremely holy; used almost exclusively in Holy of Holies.
- Dedicated to a religious purpose or a god.
- Revered in a religion.
- Morally perfect or flawless, or nearly so.
- Separated or set apart from (something unto something or someone else).
- Set apart or dedicated for a specific purpose, or for use by a single entity or person.
- Used as an intensifier in various interjections.