The most common and most likely answer to this crossword clue is the 9 letter word MOTHBALLS
I've seen this crossword clue in The Daily Telegraph
M
O
T
H
B
A
L
L
S
More clues leading to the result MOTHBALLS
Buddy explains!
The straight part
We know that "Indefinitely postpones" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case indefinitely postpones = mothballs.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 MOTHBALLS mean?
MOTHBALLS noun- (usually in plural) A small ball of chemical pesticide (typically naphthalene) and deodorant placed in or around clothing and other articles susceptible to damage from mold or moth larvae in order to protect them from this damage.