Team the French finally vanquish, having turned the screw (5)
I believe the answer is:
helix
'the screw' is the definition.
(I've seen this in another clue)
'team the french finally vanquish having turned' is the wordplay.
'team' becomes 'XI' (a football team, from Roman numerals for 11).
'the french' becomes 'le' ('the' in French).
'finally' says to take the final letters.
'having turned' is a reversal indicator.
The final letter of 'vanquish' is 'h'.
'xi'+'le'+'h'='xileh'
'xileh' backwards is 'HELIX'.
(Other definitions for helix that I've seen before include "Structure made up of a continuous series of loops" , "A three-dimensional spiral" , "that goes round and round and up and down" , "snail" , "Three-dimensional object shaped like a corkscrew" .)