Pest left scout movement (6)
I believe the answer is:
locust
'pest' is the definition.
Although both the answer and definition are singular nouns, I can't see how one could define the other.
'left scout movement' is the wordplay.
'left' becomes 'l' (common abbreviation).
'movement' indicates anagramming the letters (letters move around).
'scout' with letters rearranged gives 'ocust'.
'l'+'ocust'='LOCUST'
Can you help me to learn more?
(Other definitions for locust that I've seen before include "Migratory crop stripper" , "Large insect" , "Destroyer" , "Swarming, destructive insect" , "Part of destructive plague" .)