The most common and most likely answer to this crossword clue is the 7 letter word UNALIKE
I've seen this crossword clue in Independent
U
N
A
L
I
K
E
Buddy explains!

The straight part
We know that "different" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case different = unalike.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 UNALIKE mean?
UNALIKE adjective- Of an unlike kind; different