Free (from) (6)
(Other definitions for sans that I've seen before include "Without (Fr.)" , "Without (literary)" , "rooms for treating sick pupils" .)
'free from' is the definition.
(to rid someone of a thing is to free them from it)
This is all the clue.
(Another definition for rid of that I've seen is " Free from".)
(Other definitions for exempt that I've seen before include "Immune - absolve" , "Not subject to or liable for" , "Duty-free" , "Freed from obligation, tax etc" , "Not subject to a law" .)
(Other definitions for immune that I've seen before include "Safe from infection etc" , "Resistant, unaffected" , "Not susceptible to, say after inoculation" , "Exempt, invulnerable" , "Safe from attack" .)
'free from' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for rid that I've seen before include "Disabuse" , "Free from something unpleasant" , "Free (person of affliction)" , "Free, relieve" , "Free, disencumber" .)