Remarkable cut-down weapon in tracking system (5)
I believe the answer is:
radar
'tracking system' is the definition.
(I've seen this before)
'remarkable cut-down weapon' is the wordplay.
'remarkable' becomes 'rad' (I can't explain this - if you can you should give a lot more credence to this answer).
'cut down' means to remove the last letter.
'weapon' becomes 'arm' (synonyms).
'arm' with its final letter taken away is 'ar'.
'rad'+'ar'='RADAR'
'in' acts as a link.
Can you help me to learn more?
(Other definitions for radar that I've seen before include "Palindromic detection system" , "Instrument to detect and locate distant objects" , "Remote detection device" , "Technique using beam" , "Palindromic tracking system" .)