Serious listener at home (7)
I believe the answer is:
earnest
'serious' is the definition.
(similar in meaning)
'listener at home' is the wordplay.
'listener' becomes 'ear' (body part which hears or listens).
'at' means one lot of letters go next to another.
'home' becomes 'nest' (a bird's home).
'ear'+'nest'='EARNEST'
(Other definitions for earnest that I've seen before include "Something of value to bind a contract" , "Serious; pledge" , "Serious - advance" , "Oscar Wilde play 'The Importance of Being . . . . . . .'" , "See 1" .)