Like a slot canyon (6)
I believe the answer is:
narrow
(Other definitions for narrow that I've seen before include "Thin; taper" , "Restricted - intolerant" , "Small in breadth" , "Having little breadth" , "With sides close together" .)
I believe the answer is:
narrow
(Other definitions for narrow that I've seen before include "Thin; taper" , "Restricted - intolerant" , "Small in breadth" , "Having little breadth" , "With sides close together" .)