Bulk transport lines supplying crates (10)

I believe the answer is:

portliness

'bulk' is the definition.

'transport lines supplying crates' is the wordplay.
'crates' indicates a hidden word (crate can mean to pack in).
'PORTLINESS' can be found hidden inside 'transport lines supplying'.

I've seen this clue in The Guardian.

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.