Officer circling over headland finds detachment (8)
I believe the answer is:
coolness
'detachment' is the definition.
(thesaurus)
'officer circling over headland' is the wordplay.
'officer' becomes 'col' (short for colonel).
'circling' means one lot of letters goes inside another (circling can mean going around or containing).
'over' becomes 'o' (cricket abbreviation).
'headland' becomes 'ness' (both can mean a promontory).
'col' enclosing 'o' is 'cool'.
'cool'+'ness'='COOLNESS'
'finds' is the link.
(Another definition for coolness that I've seen is " Lack of warmth".)