Reckoning as fools fellows in street (10)
I believe the answer is:
assessment
'reckoning' is the definition.
(thesaurus)
'fools fellows in street' is the wordplay.
'fools' becomes 'asses' (ass is a kind of fool**).
'fellows' becomes 'men' (I've seen this before).
'in' means one lot of letters goes inside another.
'street' becomes 'st'.
'men' inserted into 'st' is 'sment'.
'asses'+'sment'='ASSESSMENT'
'as' acts as a link.
(Other definitions for assessment that I've seen before include "Judgement" , "Opinion" , "Examination" , "amount to be paid" , "Survey" .)