Some loss of assigned seats (5)
I believe the answer is:
sofas
'seats' is the definition.
(sofa is a kind of seat)
'some loss of assigned' is the wordplay.
'some' indicates a hidden word (some of the parts of the word are used).
'SOFAS' can be found hidden inside 'loss of assigned'.
(Other definitions for sofas that I've seen before include "Couches" , "Upholstered seats for more than one" , "Long upholstered seats" , "Furniture" , "Lounges" .)