Muscle spasm (5)
![Ross](/clue/static/ross-mug.min.png)
I believe the answer is:
cramp
'muscle spasm' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for cramp that I've seen before include "writers may be familiar with" , "restraint" , "Severe muscular pain" , "Confine - muscular spasm" , "Give too little space to" .)