Everyone steering clear of this drug den (7)
I believe the answer is:
pothole
'everyone steering clear of this' is the definition.
The definition suggests a singular noun which matches the answer.
'drug den' is the wordplay.
'drug' becomes 'pot' (slang term for cannabis).
'den' becomes 'hole' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'pot'+'hole'='POTHOLE'
Can you help me to learn more?
(Other definitions for pothole that I've seen before include "Hazard on a poorly-maintained road" , "Water-eroded cave" , "Problem in road" , "that can be problem when driving" , "Small pit in road surface" .)