What a model does when resting? (4)
I believe the answer is:
sits
'when resting?' is the definition.
I can't judge whether this definition defines the answer.
'what a model does' is the wordplay.
'what a model' becomes 'sit' ('sit' can be a synonym of 'model').
'does' becomes 's' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'sit'+'s'='SITS'
Can you help me to learn more?
(Other definitions for sits that I've seen before include "Perches" , "Poses for a painter" , "Takes an exam" , "Takes a seat for the painter" , "Poses for portrait" .)