Reproduced entertaining Russian car, power unsuited to modern needs (10)
I believe the answer is:
maladapted
'unsuited to modern needs' is the definition.
(poorly adapted for a new task)
'reproduced entertaining russian car power' is the wordplay.
'reproduced' becomes 'mated'.
'entertaining' indicates putting letters inside.
'russian car' becomes 'Lada' (Soviet Union car brand).
'power' becomes 'p'.
'lada'+'p'='ladap'
'mated' enclosing 'ladap' is 'MALADAPTED'.
(Other definitions for maladapted that I've seen before include "not suited to the task" , "unsuited to task?" , "A damp delta (anag)" .)