Bottle part
I believe the answer is:
neck
'bottle part' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for neck that I've seen before include "Isthmus - audacity" , "Part of the body - cheek" , "Narrow part of e.g. isthmus" , "sink" , "Col; impudence" .)