Rest among the lilies (3)
I believe the answer is:
lie
'rest' is the definition.
(lying is a kind of resting)
'among the lilies' is the wordplay.
'among' says the answer is hidden in the clue.
'LIE' is hidden in the letters of 'the lilies'.
(Other definitions for lie that I've seen before include "Story" , "Porky" , "Rest; deception" , "buried" , "Mistruth" .)