Tried moving head in exhaustion (9)
I believe the answer is:
tiredness
'exhaustion' is the definition.
(I've seen this before)
'tried moving head' is the wordplay.
'moving' is an anagram indicator (letters are moved around).
'head' becomes 'ness' (ness is a headland).
'tried' anagrammed gives 'tired'.
'tired'+'ness'='TIREDNESS'
'in' is the link.
(Other definitions for tiredness that I've seen before include "Exhaustion" , "Weariness" , "That's liable to occur at midnight" , "7 (anag)" , "Residents in state of fatigue" .)