Screw, prison's second in annexe (5)
I believe the answer is:
wring
'screw' is the definition.
(thesaurus)
'prison's second in annexe' is the wordplay.
'prison's second' becomes 'r' (2nd letter of 'prison').
'in' indicates putting letters inside.
'annexe' becomes 'wing' (synonyms).
'r' placed into 'wing' is 'WRING'.
(Other definitions for wring that I've seen before include "Squeeze liquid from" , "Twist forcibly" , "Squeeze water out of" , "Extract with difficulty" , "Extort; wrest" .)