The most common and most likely answer to this crossword clue is the 4 letter word HYMN
I've seen this crossword clue in The Times
H
Y
M
N
More clues leading to the result HYMN
- Church melody form — Christian, ultimately
- Song that has holy men gutted
- Religious song from that man on the radio
- Te Deum, say, not conveying the ecstasy of God?
- Reportedly not her expression of praise!
- Holy men, being extremely selective, perform religious works
- Queen admits yen to have new anthem
- Song they amend intermittently
- Song of praise suggested by that man on the radio
- Sing praises of that man on the radio
Buddy explains!

The straight part
We know that "Song" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case song = hymn.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 HYMN mean?
HYMN noun- A song of praise or worship.
- To sing a hymn.
- To praise or extol in hymns.