Mostly planning to burgle old gambling venue (6)

I believe the answer is:

casino

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

'gambling venue' is the definition.
(I've seen this before)

I can't explain the rest of the clue.

(Other definitions for casino that I've seen before include "Gaming house" , "Gaming establishment" , "Place for better" , "Building for gambling" , "Gambling establishment" .)

I've seen this clue in The Independent.

Want a hint initially instead of a full solution? Install my app