Even numbers tossing cabers (6)
I believe the answer is:
braces
'even numbers' is the definition.
'braces' can be an answer for 'numbers' (brace is a kind of number). I'm not sure about the 'even' bit.
'tossing cabers' is the wordplay.
'tossing' is an anagram indicator.
'cabers' with letters rearranged gives 'BRACES'.
(Other definitions for braces that I've seen before include "Props or trouser-supporters" , "They hold up men's trousers" , "Supports for men's trousers" , "Appliances to correct dental irregularities" , "Straps holding up trousers" .)