Nauseates one when it goes off (5)
I believe the answer is:
turns
'goes off' is the definition.
(I've seen this before)
'nauseates one when it' is the wordplay.
I cannot really see how this works, but
'it' could be 't' (abbreviation. e.g. in 'tis) and 't' is located in the answer.
The remaining letters 'urns' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for turns that I've seen before include "Rotations" , "Revolves" , "Goes off" , "Starts" , "Moves in a new direction" .)