One's not groovy, not even when twisting (5)
I believe the answer is:
saddo
'one's not groovy' is the definition.
I don't know anything about this answer so I can't judge whether it can be defined by this definition.
'not even when twisting' is the wordplay.
'not even' becomes 'odd' ('odd' is the opposite to 'even').
'when' becomes 'as' (eg 'when I walked' means 'as I walked').
'twisting' says the letters should be written backwards (letters twist back).
'odd'+'as'='oddas'
'oddas' back-to-front is 'SADDO'.
Can you help me to learn more?
(Other definitions for saddo that I've seen before include "Boring loner" , "loser" , "He's pathetic!" , "pathetic person" , "lonely person" .)