The most common and most likely answer to this crossword clue is the 7 letter word BUSTIER
I've seen this crossword clue in The Sunday Telegraph
B
U
S
T
I
E
R
Buddy explains!
The straight part
We know that "Top" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case top = bustier.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 BUSTIER mean?
BUSTIER noun- A tight-fitting women's top, often strapless, with covers the bust and sometimes extends over the belly, worn either as an undergarment or as outerwear.
- Having large breasts.