The most common and most likely answer to this crossword clue is the 10 letter word TURPENTINE
I've seen this crossword clue in The Daily Telegraph
T
U
R
P
E
N
T
I
N
E
More clues leading to the result TURPENTINE
- Oily substance from strange tree put in end of garden
- Oily substance from tree put in ground with nitrogen
- Product, primarily, in nut tree fluid
- Held in Italian city, earl gets thinner
- Stoned intern put drug in solvent
- Resin from tree put in ground around November
- Routine upset restricted sweetheart getting thinner
- Unbeliever ends in penitent suffering getting thinner
- Grind up then pound with fork getting thinner
- Source of solvent messing up internet
Buddy explains!

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 TURPENTINE mean?
TURPENTINE noun- A volatile essential oil obtained from the wood of pine trees by steam distillation; it is a complex mixture of monoterpenes; it is used as a solvent and paint thinner.
- To drain resin from (a tree) for use in making turpentine.