Slothful at home, getting benefit with book (8)
I believe the answer is:
indolent
'slothful' is the definition.
('indolent' can be a synonym of 'slothful')
'at home getting benefit with book' is the wordplay.
'at home' becomes 'in' ('in' can be similar in meaning to 'at home').
'getting' means one lot of letters go next to another.
'benefit' becomes 'dole' (I've seen this before).
'with' means one lot of letters go next to another.
'book' becomes 'nt' (I've seen this in other clues**).
'in'+'dole'+'nt'='INDOLENT'
(Other definitions for indolent that I've seen before include "Lazy, disinclined to work" , "Lethargic" , "not willing to work" , "Disinclined to exert oneself" , "Making no effort" .)