The most common and most likely answer to this crossword clue is the 9 letter word COMMANDER
I've seen this crossword clue in The Daily Telegraph
C
O
M
M
A
N
D
E
R
More clues leading to the result COMMANDER
- Someone who arrives holding mike, with officer in charge?
- Arrive, having ditched English chap, to meet the German boss
- Butterfly leads new return of red admiral’s junior
- . Naval officer to requisition one leaving base?
- Protestors harbouring bullets etc in revolution to confront queen and military authority
- Sent back in Marxist Vietnam, second left-of-centre leader
- Maiden on staff in company attached to the German officer
- Officer in charge removing Ecstasy from pocket for military use
- General punctuation nerd in a tizzy
- Perhaps monarch butterfly’s half lavender
Buddy explains!

The straight part
We know that "officer" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case officer = commander.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 COMMANDER mean?
COMMANDER noun- One who exercises control and direction of a military or naval organization.
- A naval officer whose rank is above that of a lieutenant commander and below that of captain.
- One who exercises control and direction over a group of persons.
- A designation or rank in certain non-military organizations such as NASA and various police forces.
- The chief officer of a commandry.
- A heavy beetle or wooden mallet, used in paving, in sail lofts, etc.
- A rank within an honorary order: e.g. Commander of the Legion of Honour.
- Any of various nymphalid butterflies of the Asian genus Moduza.