Small fish where brace split (7)
I believe the answer is:
scarper
'brace split' is the definition.
The answer and definition can be both to do with motion as well as being verbs in their base form.
Maybe there's an association between them I don't understand?
'small fish where' is the wordplay.
'small' becomes 's' (abbreviation - e.g. clothes size).
'fish' becomes 'carp' (carp is a kind of fish).
'where' becomes 'er' (I can't justify this - if you can you should give a lot more credence to this answer).
's'+'carp'+'er'='SCARPER'
Can you help me to learn more?
(Other definitions for scarper that I've seen before include "Hightail it, cut and run" , "Clear off!" , "bolt" , "Vamoose" , "Damage" .)