Uplifting illicit pill, ecstasy's somewhat oval (8)
I believe the answer is:
elliptic
'oval' is the definition.
(synonyms)
'uplifting illicit pill ecstasy's somewhat' is the wordplay.
'uplifting' says the letters should be written backwards.
'somewhat' indicates the answer is hidden within the clue.
'citpille' can be found hidden inside 'illicit pill ecstasys'.
'citpille' in reverse letter order is 'ELLIPTIC'.
(Other definitions for elliptic that I've seen before include "Rounded like an egg" , "circular? Not quite" , "Egg-shaped" , "Of a conical section" , "Oval" .)