Central heating smelly, not initially fresh (6)
I believe the answer is:
cheeky
'fresh' is the definition.
(I've seen this before)
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for cheeky that I've seen before include "Impudent or disrespectful" , "Insolent" , "Impudent, irreverent" , "description of the gluteus maximus?" , "Impudent or rude" .)