King sheltering solitary hopeless person (5)
I believe the answer is:
goner
'hopeless person' is the definition.
(a goner is doomed)
'king sheltering solitary' is the wordplay.
'king' becomes 'GR' (short for Georgius Rex, King George in Latin).
'sheltering' indicates putting letters inside.
'solitary' becomes 'one' (the only one).
'gr' enclosing 'one' is 'GONER'.
(Other definitions for goner that I've seen before include "No-hoper" , "Doomed person" , "Lost cause" , "One past helping" , "Hopeless case" .)