The most common and most likely answer to this crossword clue is the 5 plus 4 letter word MAJOR DOMO
I've seen this crossword clue in The Daily Telegraph
M
A
J
O
R
D
O
M
O
Buddy explains!
The straight part
We know that "Chief steward" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case chief steward = major domo.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 MAJOR DOMO mean?
MAJOR DOMO noun- The head servant or official in a royal Spanish or Italian household; later, any head servant in a wealthy household in a foreign country; a leading servant or butler.
- (Southwest) A manager of a hacienda, ranch or estate.
- Any overseer, organizer, person in command.