Melody's unprotected sex with other folk (5)
I believe the answer is:
theme
'melody's' is the definition.
(theme is a kind of melody)
'unprotected sex with other folk' is the wordplay.
'unprotected' means to look at the middle letters.
'sex' becomes 'petting' (petting is a kind of sex).
'with other folk' becomes 'heme' (I am not sure about this - if you are sure you should believe this answer much more).
The middle letter of 'petting' is 't'.
't'+'heme'='THEME'
Can you help me to learn more?
(Other definitions for theme that I've seen before include "Subject matter, topic" , "matter for discussion" , "Topic for discussion" , "Short melody" , "A subject or repeated melody" .)