Complaint when temperature taken by pushy sort (6)
I believe the answer is:
typhus
'complaint' is the definition.
(medical complaint)
'temperature taken by pushy sort' is the wordplay.
'temperature' becomes 't' (abbreviation**).
'taken by' means one lot of letters goes inside another.
'sort' is an anagram indicator.
'pushy' with letters rearranged gives 'yphus'.
't' inserted within 'yphus' is 'TYPHUS'.
'when' is the link.
(Other definitions for typhus that I've seen before include "Infectious disease transmitted by lice" , "Infectious disease with fever and purple rash" , "Dangerous fever transmitted by lice" , "Infectious disease often spread by lice" , "Acute, infectious fever" .)