Comfy seat concealed by Francis of Assisi (4)
I believe the answer is:
'comfy seat' is the definition.
(I know that Sofa are often comfortable)
'concealed by francis of assisi' is the wordplay.
'concealed by' says the answer is hidden in the clue.
'SOFA' is hidden in the letters of 'francis of assisi'.
(Other definitions for sofa that I've seen before include "Item of furniture" , "Chesterfield, maybe" , "Living room seat" , "Wide padded seat" , "Settee" .)