The most common and most likely answer to this crossword clue is the 7 letter word POSTING
I've seen this crossword clue in The Daily Telegraph
P
O
S
T
I
N
G
More clues leading to the result POSTING
Buddy explains!
The straight part
We know that "mission abroad" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case mission abroad = posting.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 POSTING mean?
POSTING verb- To hang (a notice) in a conspicuous manner for general review.
- To hold up to public blame or reproach; to advertise opprobriously; to denounce by public proclamation.
- To carry (an account) from the journal to the ledger.
- To inform; to give the news to; to make acquainted with the details of a subject; often with up.
- To pay (a blind).
- To put content online, usually through a publicly accessible mean, such as a video channel, gallery, message board, blog etc.
- To travel with relays of horses; to travel by post horses, originally as a courier.
- To travel quickly; to hurry.
- To send (an item of mail etc.) through the postal service.
- (horse-riding) To rise and sink in the saddle, in accordance with the motion of the horse, especially in trotting.
- To publish (a message) to a newsgroup, forum, blog, etc.
- To enter (a name) on a list, as for service, promotion, etc.
- To assign to a station; to set; to place.
- The action of the verb to post.
- An item inserted into a register, ledger or diary.
- A message posted to a computerized bulletin board, a newsgroup, a blog, etc.
- The place where a soldier or airman is posted for duty; the time spent there.