Drowsy and moving unsteadily, about close to exhaustion (7)
I believe the answer is:
yawning
'drowsy' is the definition.
('yawning' can be a synonym of 'drowsy')
'and moving unsteadily about close to exhaustion' is the wordplay.
I cannot really understand how this works, but
'and' could be 'n' (common abbreviation for 'and') and 'n' is found within the answer.
'about' could be 'a' (abbreviation in Chambers) and 'a' is located in the answer.
'close' could be 'win' (win is a kind of close) and 'win' is present in the remaining letters.
This may be the basis of clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for yawning that I've seen before include "Not apparently interested" , "Drowsy" , "showing sign of tiredness?" , "showing sign of fatigue?" , "Showing boredom?" .)