Oh, put back present one's held unwillingly (7)
I believe the answer is:
hostage
'one's held unwillingly' is the definition.
(hostages are held against their will)
'oh put back present' is the wordplay.
'put back' says the letters should be written backwards.
'present' becomes 'stage' (synonyms).
'oh' written backwards gives 'ho'.
'ho'+'stage'='HOSTAGE'
(Other definitions for hostage that I've seen before include "Person held by kidnapper for ransom" , "Prisoner - pawn" , "Prisoner kept as security" , "One caught" , "person captive to fortune" .)