Curved entryway (4)
I believe the answer is:
arch
'curved entryway' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for arch that I've seen before include "Prefix meaning chief - maybe an angel" , "Masonry construction for spanning an opening" , "Affectedly playful (4)" , "Curve of a bridge" , "Knowing, sly" .)