Two held lorry up lacking any practical value (12)

I believe the answer is:

otherworldly

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

'two' is the definition.
Both the definition and answer are adjectives. Perhaps they are linked in a way I don't understand?

I don't understand how the rest of the clue works.

Can you help me to learn more?

(Other definitions for otherworldly that I've seen before include "Relating to an imaginary realm" , "Out of touch with reality" , "focused on hereafter" , "Spiritual; imaginary" , "Ethereal" .)

I've seen this clue in The Times and The Sunday 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.