New marker is strict (6)
I believe the answer is:
narrow
'strict' is the definition.
(thesaurus)
'new marker' is the wordplay.
'new' becomes 'n'.
'marker' becomes 'arrow' (I've seen this before).
'n'+'arrow'='NARROW'
'is' is the link.
(Other definitions for narrow that I've seen before include "Small-minded" , "Strait or confined" , "Pinched" , "Strait; close" , "Strict" .)