Dress is raised over top of head with feet (5)
I believe the answer is:
'dress' is the definition.
(shift is a kind of dress)
'is raised over top of head with feet' is the wordplay.
'raised' says the letters should be written backwards.
'over' means one lot of letters goes inside another.
'top of' indicates taking the first letters.
'with' is a charade indicator (letters next to each other).
'feet' becomes 'ft' (I've seen this in other clues**).
The first letter of 'head' is 'h'.
'is' back-to-front is 'si'.
'si' going around 'h' is 'shi'.
(Other definitions for shift that I've seen before include "underskirt" , "Time when group of people are working" , "Change position" , "Alter" , "Move (fast!)" .)