The most common and most likely answer to this crossword clue is the 9 letter word TOUCHWOOD
I've seen this crossword clue in The Daily Telegraph
T
O
U
C
H
W
O
O
D
Buddy explains!
The straight part
We know that "it’s inflammable" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case it’s inflammable = touchwood.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 TOUCHWOOD mean?
TOUCHWOOD noun- Decayed wood used as tinder; punk.