Body Romeo hides in thicket (6)
I believe the answer is:
corpse
'body' is the definition.
(a corpse is a dead body)
'romeo hides in thicket' is the wordplay.
'romeo' becomes 'r' (phonetic alphabet: alpha, bravo, charlie etc.).
'hides in' means one lot of letters goes inside another.
'thicket' becomes 'copse' (synonyms).
'r' put into 'copse' is 'CORPSE'.
(Other definitions for corpse that I've seen before include "Dead bodies" , "Dead body" , "Cadaver, dead person" , "Roof beam" .)