The most common and most likely answer to this crossword clue is the 7 letter word POTHEAD
I've seen this crossword clue in Financial Times
P
O
T
H
E
A
D
More clues leading to the result POTHEAD
Buddy explains!
The straight part
We know that "puffer on a spliff?" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case puffer on a spliff? = pothead.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 POTHEAD mean?
POTHEAD noun- A person who smokes cannabis frequently, to excess.