The most common and most likely answer to this crossword clue is the 11 letter word FARTHINGALE
F
A
R
T
H
I
N
G
A
L
E
Buddy explains!
The straight part
We know that "expansive habit" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case expansive habit = farthingale.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 FARTHINGALE mean?
FARTHINGALE noun- A hooped structure in cloth worn to extend the skirt of women's dresses; a hooped petticoat.