The most common and most likely answer to this crossword clue is the 8 letter word RIGHT-ON
I've seen this crossword clue in Independent
R
I
G
H
T
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N
More clues leading to the result RIGHT-ON
Buddy explains!
The straight part
We know that "trendy" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case trendy = right-on.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 RIGHT-ON mean?
RIGHT-ON adjective- Possessing political and social views that are considered to be fashionable and left-wing.