Knight requires weapon -- and fortune (8)
I believe the answer is:
lancelot
'knight' is the definition.
(thesaurus)
'weapon and fortune' is the wordplay.
'weapon' becomes 'lance' (lance is a kind of weapon).
'and' says to put letters next to each other.
'fortune' becomes 'lot' ('lot' can be a synonym of 'fortune').
'lance'+'lot'='LANCELOT'
'requires' acts as a link.
(Other definitions for lancelot that I've seen before include "One of King Arthur's knights, lover of Guinevere" , "queen's lover" , "Arthurian knight, Guinevere's lover" , "K?" , "Round Table member" .)