Irregular method followed by section of a hospital (7)
I believe the answer is:
wayward
'irregular' is the definition.
(thesaurus)
'method followed by section of a hospital' is the wordplay.
'method' becomes 'way' (way of doing something).
'followed by' is a charade indicator (letters next to each other).
'section of a hospital' becomes 'ward' (hospitals have wards).
'way'+'ward'='WAYWARD'
(Other definitions for wayward that I've seen before include "Unpredictable, wilful" , "Perversely independent" , "Undisciplined, headstrong" , "Resistant to discipline" , "Not obedient or easily controlled" .)