Is familiar we hear with happy bunch... (7)
I believe the answer is:
nosegay
'bunch' is the definition.
(I have seen 'Bunch of flowers ' mean 'nosegay' so perhaps 'bunch' could also mean 'nosegay')
'is familiar we hear with happy' is the wordplay.
'is familiar' becomes 'knows'.
'we hear' shows a homophone (sound like).
'with' says to put letters next to each other.
'happy' becomes 'gay' ('gay' can be similar in meaning to 'happy').
'knows' is a homophone of 'nose'.
'nose'+'gay'='NOSEGAY'
(Other definitions for nosegay that I've seen before include "Floral offering" , "Small bouquet" , "Flower arrangement" , "Corsage" , "Gone, say (anag)" .)