Throttling, giving a signal to turn around (13)
I believe the answer is:
strangulation
'throttling' is the definition.
('strangulation' can be a synonym of 'throttling')
'a signal to turn around' is the wordplay.
'around' indicates anagramming the letters.
'a'+'signal'+'to'+'turn'='asignaltoturn'
'asignaltoturn' anagrammed gives 'STRANGULATION'.
'giving' is the link.
(Other definitions for strangulation that I've seen before include "The choking off of a flow" , "The choking off of a blood vessel" , "murder" , "Process of choking" , "Act of choking" .)