Indicates assent, as the sleepy man does (4)
I believe the answer is:
nods
This clue might be a double definition.
'indicates assent' is the first definition.
(I've seen this in another clue)
'the sleepy man does' is the second definition.
The definition and answer can be both related to bodily activities as well as being verbs in their -s form.
Perhaps they are linked in a way I don't understand?
'as' acts as a link.
Can you help me to learn more?
(Other definitions for nods that I've seen before include "Inclines head" , "Affirmative gestures" , "Indicates assent" , "gestures in agreement" , "Shows assent" .)