The most common and most likely answer to this crossword clue is the 4 letter word MOAN
I've seen this crossword clue in Financial Times
M
O
A
N
More clues leading to the result MOAN
- Fellow keeping oxen at first for beef
- Beef heart stolen from buccaneer
- Complaint from empty fellow, as it were
- Hungry fellow, as it were, gets bellyache
- Old bird sitting on pole is grouse
- Keen old fellow coming round
- Nothing about which fellow gets to complain
- Duck caught by male grouse
- Zoo finally admitted to chap’s complaint
- Starts of mozzarella, olives and Neapolitan beef
Buddy explains!

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 MOAN mean?
MOAN noun- A low, mournful cry of pain, sorrow or pleasure
- To complain about; to bemoan, to bewail; to mourn.
- To grieve.
- To distress (someone); to sadden.
- To make a moan or similar sound.
- To say in a moan, or with a moaning voice.
- To complain; to grumble.