Of most restricted width (9)
I believe the answer is:
narrowest
(Other definitions for narrowest that I've seen before include "Most confined" , "Slightest" , "Most slender" , "least with room to spread wings?" , "Being most thin" .)
I believe the answer is:
narrowest
(Other definitions for narrowest that I've seen before include "Most confined" , "Slightest" , "Most slender" , "least with room to spread wings?" , "Being most thin" .)