Very quiet in the grass, and joyful (5)
I believe the answer is:
happy
'joyful' is the definition.
('happy' can be similar in meaning to 'joyful')
'very quiet in the grass' is the wordplay.
'very quiet' becomes 'pp' (**).
'in the' means one lot of letters goes inside another.
'grass' becomes 'hay' (I have seen 'Mown grass ' mean 'hay' so perhaps 'grass' could also mean 'hay').
'pp' going within 'hay' is 'HAPPY'.
'and' acts as a link.
(Other definitions for happy that I've seen before include "Fortunate; content" , "Gleeful" , "Showing pleasure" , "Pleased, content" , "Doc's smiling pal" .)