Singer on drug taking break in squalid room (7)
I believe the answer is:
rathole
'squalid room' is the definition.
(I've seen this before)
'singer on drug taking break in' is the wordplay.
'singer' becomes 'rat' (both can mean an informant).
'on' is a charade indicator (letters next to each other) (in a down clue, letters appear on others).
'drug' becomes 'e' (E is another name for ecstasy).
'taking' indicates putting letters inside.
'break in' becomes 'hol' (I can't justify this - if you can you should believe this answer much more).
'rat'+'e'='rate'
'rate' enclosing 'hol' is 'RATHOLE'.
Can you help me to learn more?
(Other definitions for rathole that I've seen before include "pit" , "Rodent entrance" , "Sign of infestation" , "squalid room" , "Dirty room" .)