Weak start to Guardian article (5)
I believe the answer is:
thing
'article' is the definition.
(both can mean an object)
'weak start to guardian' is the wordplay.
'weak' becomes 'thin' (similar in meaning).
'start to' says to take the initial letters.
The initial letter of 'guardian' is 'g'.
'thin'+'g'='THING'
(Other definitions for thing that I've seen before include "Individual object" , "Night (anag)" , "cup of tea" , "Individual unit" , "Object; gadget" .)