Pay attention to legal right crossing the road (6)
I believe the answer is:
listen
'pay attention to' is the definition.
(thesaurus)
'legal right crossing the road' is the wordplay.
'legal right' becomes 'lien' (I've seen this before**).
'crossing' indicates putting letters inside.
'the road' becomes 'st'.
'lien' enclosing 'st' is 'LISTEN'.
(Other definitions for listen that I've seen before include "16 (anag.)" , "Follow advice" , "Make an effort to hear" , "Pay attention and hear" , "Harken" .)