Stride to portal, say (4)
I believe the answer is:
gait
'stride' is the definition.
(I've seen this in another clue)
'portal say' is the wordplay.
'portal' becomes 'gate' (I've seen this in another clue).
'say' indicates a 'sounds like' (homophone) clue.
'gate' sounds like 'GAIT'.
'to' is the link.
(Other definitions for gait that I've seen before include "Style of walking" , "Manner of walking or running" , "Carriage" , "walkway?" , "Method of moving" .)