Complaint tabloid had time to overturn (7)
I believe the answer is:
tetanus
'complaint' is the definition.
(tetanus is a kind of health problem)
'tabloid had time to overturn' is the wordplay.
'tabloid' becomes 'sun' (The Sun, UK newspaper).
'had' becomes 'ate' ('have' can mean 'eat').
'time' becomes 't' (abbreviation).
'to overturn' is a reversal indicator.
'sun'+'ate'+'t'='sunatet'
'sunatet' reversed gives 'TETANUS'.
(Other definitions for tetanus that I've seen before include "Infection of the central nervous system" , "Locker" , "Disease causing muscular spasms" , "Infection from wound" , "Attunes to disease from dog-bite" .)