The most common and most likely answer to this crossword clue is the 4 letter word IDEM
I've seen this crossword clue in The Guardian
I
D
E
M
More clues leading to the result IDEM
- Fish with a bit of may, ten cents
- TV etc mostly coming up the same
- The same as marks primarily found on fish
- Part in Pride movie, as just quoted
- Eat modish goulash, not as hot as before
- Average cut in half about the same
- Early edition of Come Dine with Me returns – no different from before!
- As just mentioned, set up intermediation
- Much of media backing is the same
Buddy explains!

The straight part
We know that "As just mentioned" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case as just mentioned = idem.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 IDEM mean?
IDEM pronoun- The same.