Drudgery only an ass would do? (10)

I believe the answer is:

donkeywork

I'm a little stuck... Click here to teach me more about this clue!

'drudgery' is the definition.
(synonyms)

'ass would do?' is the wordplay.
'ass' becomes 'donkey' (donkey is a kind of ass).
'would do?' becomes 'work' (I can't justify this - if you can you should believe this answer much more).
'donkey'+'work'='DONKEYWORK'

'only an' acts as a link.
This may not be correct. Some or all of it may be part of another bit of the clue.

Can you help me to learn more?

I've seen this clue in The Irish Independent.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.