The most common and most likely answer to this crossword clue is the 9 letter word ARISTOTLE
I've seen this crossword clue in The Times
A
R
I
S
T
O
T
L
E
More clues leading to the result ARISTOTLE
- Thinking Greek child left during a hike
- Emerge bearing child close to natural philosopher
- Noble title—it’s unwanted, he thought
- Earl let loose philosopher
- Child in Israel infuriated old teacher
- Happen to come across sum left for old teacher
- Great thinker once designing toilets south of the centre of Kilmarnock
- Philosopher is alert to changes
- Old Greek totaliser cock-up
- Philosopher tries a lot when in trouble
Buddy explains!
The straight part
We know that "Thinking Greek" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case thinking greek = aristotle.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.