The most common and most likely answer to this crossword clue is the 8 letter word BECOMING
I've seen this crossword clue in The Daily Telegraph
B
E
C
O
M
I
N
G
Buddy explains!

The straight part
We know that "attractive" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case attractive = becoming.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 BECOMING mean?
BECOMING verb- To arrive, come (to a place).
- To come about; happen; come into being; arise.
- Begin to be; turn into.
- To be proper for; to beseem.
- Of an adornment, piece of clothing etc.: to look attractive on (someone).
- The act or process by which something becomes.
- Pleasingly suitable; fit; congruous; beautiful
- Decent, respectable