Greek character getting into twist in practice (4-2)
I believe the answer is:
warm-up
'practice' is the definition.
(thesaurus)
'greek character getting into twist' is the wordplay.
'greek character' becomes 'mu' (letter from the Greek alphabet).
'getting into' means one lot of letters goes inside another.
'twist' becomes 'warp' (I've seen this before**).
'mu' placed inside 'warp' is 'WARM-UP'.
'in' is the link.
(Other definitions for warm-up that I've seen before include "Preliminary exercising" , "Preparatory exercises before an event" , "Prepare for athletic contest by exercising beforehand" , "Preliminary exercise" , "Rehearse" .)