John the estate agent's sign impresses paper (6)
I believe the answer is:
toilet
'john' is the definition.
(synonyms)
'the estate agent's sign impresses paper' is the wordplay.
'the estate agent's sign' becomes 'tolet' (as in a 'to let' sign on a property).
'impresses' indicates putting letters inside (some letters pressed into others).
'paper' becomes 'i' (UK newspaper).
'tolet' going around 'i' is 'TOILET'.
(Other definitions for toilet that I've seen before include "Plumbing fixture" , "something to go on?" , "WC" , "Waste disposal unit" , "Smallest room" .)