The most common and most likely answer to this crossword clue is the 9 letter word PISTACHIO
P
I
S
T
A
C
H
I
O
More clues leading to the result PISTACHIO
- Rarely has one topic that one can crack
- Greek character in patio's sickly, sort of green
- Green Party at first is to include what’s essential to teaching
- 18 cops and 1 crazy nut
- One absorbed by weird topic has to be a nut
- His topic, a strange nut
- Light green potash ICI manufactured
- Tricky chip is to a green
- Nut‘s broken as I chop it
- Knights quitting bar following sanctimonious nut
Buddy explains!

The straight part
We know that "Green" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case green = pistachio.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 PISTACHIO mean?
PISTACHIO noun- A deciduous tree (Pistacia vera) grown in parts of Asia for its drupaceous fruit.
- The nutlike fruit of this tree.
- (color) A pale green colour, like that of a pistachio seed.