Navigational aid for a woman in a car (5)
I believe the answer is:
radar
'navigational aid' is the definition.
(I've seen this before)
'a woman in a car' is the wordplay.
'a woman' becomes 'ada'.
'in' is an insertion indicator.
'a car' becomes 'rr' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'ada' put inside 'rr' is 'RADAR'.
'for' is the link.
Can you help me to learn more?
(Other definitions for radar that I've seen before include "System for locating distant objects" , "Radio detection system" , "Aircraft detection system" , "Position detector using radio wave pulses" , "Method of detection" .)