Sweet tablet twisted into spiral (8)
I believe the answer is:
lollipop
'sweet' is the definition.
(lollipop is a kind of sweet)
'tablet twisted into spiral' is the wordplay.
'tablet' becomes 'pill' (synonyms).
'twisted' says the letters should be written backwards.
'into' means one lot of letters goes inside another.
'spiral' becomes 'loop' (I've seen this in another clue).
'pill' back-to-front is 'llip'.
'llip' placed within 'loop' is 'LOLLIPOP'.
(Other definitions for lollipop that I've seen before include "Boiled sweet" , "Confectionery" , "children love it" , "Sweet for suckers?" , "Ice confection" .)