Take ecstasy in club (4)
I believe the answer is:
bear
'take' is the definition.
(synonyms)
'ecstasy in club' is the wordplay.
'ecstasy' becomes 'e' (informal term for the drug).
'in' is an insertion indicator.
'club' becomes 'bar' (I can't explain this - if you can you should believe this answer much more).
'e' inserted inside 'bar' is 'BEAR'.
Can you help me to learn more?
(Other definitions for bear that I've seen before include "Support; brutish person" , "It may be polar or grizzly" , "Relating to charged particles" , "Endure; animal" , "Press (on) - approach threateningly" .)