Pathway regulation overturned by King (4)
I believe the answer is:
walk
'pathway' is the definition.
(thesaurus)
'regulation overturned by king' is the wordplay.
'regulation' becomes 'law' (I've seen this in another clue).
'overturned' says the letters should be written backwards.
'by' means one lot of letters go next to another.
'king' becomes 'K' (abbreviation for king in chess).
'law' reversed gives 'wal'.
'wal'+'k'='WALK'
(Other definitions for walk that I've seen before include "Perambulate" , "Stroll" , "Amble" , "Go on foot" , "Travel on foot" .)