Stop putting unknown in Times puzzle (6)
I believe the answer is:
stymie
'stop' is the definition.
(thesaurus)
'unknown in times puzzle' is the wordplay.
'unknown' becomes 'y' (algebra).
'in' means one lot of letters goes inside another.
'puzzle' indicates anagramming the letters.
'times' with letters rearranged gives 'stmie'.
'y' placed inside 'stmie' is 'STYMIE'.
'putting' is the link.
(Other definitions for stymie that I've seen before include "Block or thwart an activity" , "Block or thwart, perhaps in golf" , "Block or thwart, perhaps on putting green" , "Block or obstruct as in golf (6)" , "Block or thwart, as on golf course" .)