In a way, provided riddle (4)
I believe the answer is:
sift
'riddle' is the definition.
(thesaurus)
'in a way provided' is the wordplay.
'in' indicates putting letters inside.
'a way' becomes 'st'.
'provided' becomes 'if'.
'st' placed around 'if' is 'SIFT'.
(Other definitions for sift that I've seen before include "Sieve, examine closely" , "Sort carefully" , "Pass though a sieve" , "Get lumps from (flour)" , "Riddle, sieve" .)