The most common and most likely answer to this crossword clue is the 7 letter word COBNUTS
I've seen this crossword clue in The Guardian
C
O
B
N
U
T
S
Buddy explains!
The straight part
We know that "hazels" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case hazels = cobnuts.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 COBNUTS mean?
COBNUTS noun- The nut of the common hazel (Corylus avellana); hazelnut.
- A specific cultivated variety of hazelnut, also known as the Kentish cobnut.
- A game played by children with nuts.