Nurse is out of sorts for a time (7)
I believe the answer is:
sunrise
'time' is the definition.
(I know that sunrise is a type of hour)
'nurse is out of sorts' is the wordplay.
'out of sorts' indicates anagramming the letters (not its usual self).
'nurse'+'is'='nurseis'
'nurseis' is an anagram of 'SUNRISE'.
'for a' acts as a link.
(Other definitions for sunrise that I've seen before include "It's preceded by dawn" , "See 21" , "Time of full daylight" , "everyday occurrence in the East" , "Dawning of the day" .)