Marine disorientated on top of Trump Tower (7)
I believe the answer is:
minaret
'tower' is the definition.
(minaret is a kind of tower)
'marine disorientated on top of trump' is the wordplay.
'disorientated' is an anagram indicator.
'on top of' indicates taking the first letters (I've seen 'on top' mean this).
The first letter of 'trump' is 't'.
'marine' anagrammed gives 'minare'.
'minare'+'t'='MINARET'
(Other definitions for minaret that I've seen before include "Mosque turret" , "Tower from which muezzin calls Muslims to prayer" , "Tower attached to mosque" , "Slender tower with balconies" , "Raiment worn on mosque tower" .)