Suggest tossing out staple (9)
I believe the answer is:
postulate
'suggest' is the definition.
(thesaurus)
'tossing out staple' is the wordplay.
'tossing' is an anagram indicator.
'out'+'staple'='outstaple'
'outstaple' anagrammed gives 'POSTULATE'.
(Other definitions for postulate that I've seen before include "Let sap out in order to claim something" , "Assume as axiom" , "Suppose" , "That which is assumed" , "Put forward" .)