Detective Sergeant arresting little British idiots (6)
I believe the answer is:
dweebs
'idiots' is the definition.
I don't know anything about this answer so I cannot judge whether it can be defined by this definition.
'detective sergeant arresting little british' is the wordplay.
'detective sergeant' becomes 'DS' (abbreviation for detective sergeant).
'arresting' is an insertion indicator.
'little' becomes 'wee' (similar in meaning).
'british' becomes 'b' (abbreviation e.g. in BBC).
'wee'+'b'='weeb'
'ds' going around 'weeb' is 'DWEEBS'.
Can you help me to learn more?
(Other definitions for dweebs that I've seen before include "They're socially inept!" , "nerds" .)