The most common and most likely answer to this crossword clue is the 5 letter word FAKIR
I've seen this crossword clue in The Sunday Telegraph
F
A
K
I
R
More clues leading to the result FAKIR
- Ascetic in the distance crossing Himalayan mountain
- Mendicant king with fine clothing
- Holy man just needs to hold tip of prick
- Just retaining King’s ascetic
- He takes to his bed – sharpish
- Holy man seeing a king hiding in tree
- King taken in by light-headed religious ascetic
- Just about the end of walk for poor ascetic
- Holy man just restraining knight
- He takes to his bed, sharpish
Buddy explains!

The straight part
We know that "religious ascetic" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case religious ascetic = fakir.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 FAKIR mean?
FAKIR noun- A faqir, owning no personal property and usually living solely off alms.
- (Hindu) An ascetic mendicant, especially one who performs feats of endurance or apparent magic.
- Someone who takes advantage of the gullible through fakery, especially of a spiritual or religious nature.