The most common and most likely answer to this crossword clue is the 7 letter word BRIEFLY
I've seen this crossword clue in The Daily Telegraph
B
R
I
E
F
L
Y
More clues leading to the result BRIEFLY
- Insect on soft cheese for a short time
- In short coat from bazaar that is smart
- Extremely lively after lawyer gets to the point
- Layer of eggs on cheese for a moment
- Insect found under cheese, in a word
- In short cheese attracts insect
- Insect going after cheese for a short time
- Brother — that is cunning, in short
Buddy explains!

The straight part
We know that "In short" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case in short = briefly.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 BRIEFLY mean?
BRIEFLY adverb- (manner) In a brief manner, summarily.
- (duration) For a brief period.
- To be brief, in short.