Senior nurse in Leeds is terrible (6)
I believe the answer is:
sister
'senior nurse' is the definition.
(I've seen this before)
'in leeds is terrible' is the wordplay.
'in' indicates a hidden word.
'SISTER' is hidden within 'leeds is terrible'.
(Other definitions for sister that I've seen before include "twin?" , "Close female relative" , "A kinswoman" , "Tender" , "'Nurse, nun or relative (6)'" .)