Nausea from sis's neck wound (8)
I believe the answer is:
sickness
'nausea' is the definition.
(I know that nausea can be written as sickness)
'sis's neck wound' is the wordplay.
'wound' indicates an anagram (wound can mean twisted or turned around).
'siss'+'neck'='sissneck'
'sissneck' anagrammed gives 'SICKNESS'.
'from' acts as a link.
(Other definitions for sickness that I've seen before include "It's not looking good" , "State of ill-health, malady" , "Illness, malady" , "Illness, disease" , "Infirmity" .)