The most common and most likely answer to this crossword clue is the 9 letter word DAIRYMAID
I've seen this crossword clue in Financial Times
D
A
I
R
Y
M
A
I
D
More clues leading to the result DAIRYMAID
- Midday air aroused farmworker
- Farm worker rejected flood relief
- Person milking crowds after backing charity
- Farm worker cheated having taken in nonchalant old woman
- Retreating army to help farmhand
- Why speaking with Maria did wrong by old farm worker
- Performed gripping song by girl about old farm worker
- 14 heading over to assist farm girl
- Host returned to assist worker on farm
- Fresh meal frequently eaten by accomplished farm worker
Buddy explains!

The straight part
We know that "old farm worker" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case old farm worker = dairymaid.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 DAIRYMAID mean?
DAIRYMAID noun- A woman who works in a dairy.