Halt after turning around four turns (6)
I believe the answer is:
pivots
'turns' is the definition.
(pivoting is a kind of turning)
'halt after turning around four' is the wordplay.
'halt after turning' becomes 'pots' (I can't justify this - if you can you should believe this answer much more).
'around' is an insertion indicator.
'four' becomes 'IV' (Roman numerals for four).
'pots' enclosing 'iv' is 'PIVOTS'.
Can you help me to learn more?
(Other definitions for pivots that I've seen before include "Rotates" , "Swivels" .)