The most common and most likely answer to this crossword clue is the 9 letter word DANDIFIED
I've seen this crossword clue in The Times
D
A
N
D
I
F
I
E
D
More clues leading to the result DANDIFIED
Buddy explains!

The straight part
We know that "Foppish" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case foppish = dandified.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 DANDIFIED mean?
DANDIFIED adjective- Characteristic (in dress and habits) of a dandy
- To dress as, or to adopt the style of, a dandy.