Deer displayed by hostages (4)
I believe the answer is:
stag
'deer' is the definition.
(stag is a kind of deer)
'displayed by hostages' is the wordplay.
'displayed by' indicates the answer is hidden within the clue.
'STAG' can be found hidden inside 'hostages'.
(Other definitions for stag that I've seen before include "Excluding women" , "without female escort" , "Male at party?" , "Hunted animal" , "A fully-grown male deer" .)