American among others picked up — a stunner (5)
I believe the answer is:
taser
'a stunner' is the definition.
(I've seen this before)
'american among others picked up' is the wordplay.
'american' becomes 'a' (common abbreviation - e.g. in organisation names).
'among' means one lot of letters goes inside another.
'others' becomes 'rest' (I've seen this in other clues).
'picked up' says the letters should be written backwards.
'a' inserted inside 'rest' is 'resat'.
'resat' back-to-front is 'TASER'.
(Other definitions for taser that I've seen before include "Electrical weapon" , "Stunning weapon" , "Shocking device used by the police?" , "A shocking thing" , "Device used to stun someone temporarily" .)