Spasm of the diaphragm (6)
I believe the answer is:
hiccup
'spasm of the diaphragm' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for hiccup that I've seen before include "Minor hitch" , "Temporary setback (colloq.)" , "Involuntary glottal closure" , "Minor setback" , "Minor problem" .)