Show former lover one piece on hotel (7)
I believe the answer is:
exhibit
'show' is the definition.
(I know that show can be written as exhibit)
'former lover one piece on hotel' is the wordplay.
'former lover' becomes 'ex' (an ex-lover).
'one' becomes 'i' (Roman numeral).
'piece' becomes 'bit' (synonyms).
'on' is a charade indicator (letters next to each other).
'hotel' becomes 'h' (phonetic alphabet: alpha, bravo, charlie etc.).
'i'+'bit'='ibit'
'ibit' put after 'h' is 'hibit'.
'ex'+'hibit'='EXHIBIT'
(Other definitions for exhibit that I've seen before include "Publicly display" , "Manifest" , "Put on display" , "Something shown in public" , "Item in show" .)