Eat nuts, unfortunately getting lockjaw (7)
I believe the answer is:
tetanus
'lockjaw' is the definition.
('tetanus' can be a synonym of 'lockjaw')
'eat nuts unfortunately' is the wordplay.
'unfortunately' indicates an anagram.
'eat'+'nuts'='eatnuts'
'eatnuts' with letters rearranged gives 'TETANUS'.
'getting' acts as a link.
(Other definitions for tetanus that I've seen before include "Disease known as lockjaw from rabid dog bite" , "Disease causing muscular spasms" , "Infection of the central nervous system" , "Bacterial disease" , "infectious disease" .)