Arrest Fred's accomplice for something spicy (4,6)

I believe the answer is:

stem ginger

I'm a little stuck... Click here to teach me more about this clue!

'something spicy' is the definition.
I know that 'spicy' relates to this answer.

'arrest fred's accomplice' is the wordplay.
'arrest' becomes 'stem'.
'fred's accomplice' becomes 'ginger' (Fred Astaire and Ginger Rogers).
'stem'+'ginger'='STEM GINGER'

'for' acts as a link.

Can you help me to learn more?

(Other definitions for stem ginger that I've seen before include "Merging set (anag.)" , "It's tasty" , "spicy ingredient" , "sort of ice cream" , "As food" .)

I've seen this clue in The Everyman puzzle in The Observer.

Want a hint initially instead of a full solution? Install my app