Tough quality of game stuffed with hock? (9)

I believe the answer is:

chewiness

I'm a little stuck... Click here to teach me more about this clue!

'tough quality' is the definition.
The definition suggests a singular noun which matches the answer.

'game stuffed with hock?' is the wordplay.
'game' becomes 'chess' (board game).
'stuffed with' is an insertion indicator (some letters get stuffed inside).
'hock?' becomes 'wine' (hock is a kind of wine).
'chess' placed around 'wine' is 'CHEWINESS'.

'of' acts as a link.

Can you help me to learn more?

I've seen this clue in The Times.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.