Cancel directions to portal (6)
I believe the answer is:
negate
'cancel' is the definition.
(I've seen this in another clue)
'directions to portal' is the wordplay.
'directions' becomes 'ne' (I've seen this in other clues).
'to portal' becomes 'gate' (I've seen this in another clue).
'ne'+'gate'='NEGATE'
(Other definitions for negate that I've seen before include "Render ineffective" , "Countermand" , "Opera by Puccini" , "Cause to have no effect" , "Nullify - deny the existence of" .)