Cryptic crossword clue
It was extravagant also to purchase black belt 9

The most common and most likely answer to this crossword clue is the 9 letter word WAISTBAND

I've seen this crossword clue in The Daily Telegraph
W
A
I
S
T
B
A
N
D

Buddy explains!

The straight part
We know that "belt" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case belt = waistband.
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 WAISTBAND mean?

WAISTBAND noun
  1. A band of fabric encircling the waist, especially a part of a pair of pants or a skirt.

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