Jerk resorts to get married (5)
I believe the answer is:
spasm
'jerk' is the definition.
(I've seen this before)
'resorts to get married' is the wordplay.
'resorts' becomes 'spas' (spa is a kind of resort).
'to get' is a charade indicator (letters next to each other).
'married' becomes 'm'.
'spas'+'m'='SPASM'
(Other definitions for spasm that I've seen before include "Burst" , "sudden movement" , "Jerk" , "Involuntary muscular movement" , "cramp" .)