Crossword Genius

I'm done with pub - virtually ruined smoking area (5,3)

Ross

I believe the answer is:

opium den

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

'smoking area' is the definition.
The definition and answer can be both man-made objects as well as being singular nouns.
Maybe they are linked in a way I don't understand?

'i'm done with pub virtually ruined' is the wordplay.
'with' means one lot of letters go next to another.
'virtually' means to remove the last letter (virtually all of the word).
'ruined' indicates anagramming the letters.
'pub' with its last letter removed is 'pu'.
'im'+'done'='imdone'
'imdone' after 'pu' is 'puimdone'.
'puimdone' anagrammed gives 'OPIUM-DEN'.

Can you help me to learn more?

(Other definitions for opium den that I've seen before include "Place to buy and smoke dope" , "place for addicts" , "Place to take drugs" , "smoke-filled room" .)

I've seen this clue in The Independent.
Want a hint initially instead of a full solution? Install my app