The most common and most likely answer to this crossword clue is the 7 letter word APOCOPE
A
P
O
C
O
P
E
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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 = apocope.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 APOCOPE mean?
APOCOPE noun- (narrow sense) The loss or omission of the last vowel in a word, together with any consonants that follow it.
- The loss or omission of a sound or syllable from the end of a word.