The most common and most likely answer to this crossword clue is the 5 letter word TITUS
I've seen this crossword clue in Financial Times
T
I
T
U
S
More clues leading to the result TITUS
- Emperor's hearing complaint tavern ignored
- A pastoral letter: some felt it useful
- Strict nurse regularly scrubbed Roman emperor
- American singer’s first book
- No-account Roman historian's religious book
- Book from America with songbird at front?
- Prominent at last in rising become emperor
- Emperor keeping sixth of treasure in chest, commonly?
- Square it with American for holy work
- Testimony primarily introduced to fit up emperor
Buddy explains!

The straight part
We know that "holy work" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case holy work = titus.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.