Stick close to concierge in block (4)
I believe the answer is:
bear
'stick' is the definition.
(thesaurus)
'close to concierge in block' is the wordplay.
'close to' suggests the final letters (the 'close' to the word).
'in' is an insertion indicator.
'block' becomes 'bar' (block can mean to ban or bar).
The final letter of 'concierge' is 'e'.
'e' placed within 'bar' is 'BEAR'.
(Other definitions for bear that I've seen before include "Large, shaggy-coated mammal" , "Go" , "Huge carnivore" , "Carry - tolerate" , "Hack" .)