Sons in poor health — would this bring on nausea? (7)
I believe the answer is:
sailing
'would this bring on nausea?' is the definition.
The definition suggests a singular noun which matches the answer.
'sons in poor health' is the wordplay.
'sons' becomes 's'.
'in poor health' becomes 'ailing' (an ailing person is unwell).
's'+'ailing'='SAILING'
Can you help me to learn more?
(Other definitions for sailing that I've seen before include "Water sport" , "event" , "Marine sport" , "Going by, eg, yacht" , "Eg, yachting" .)