In addition to 6. Jigger, indeed this is an alleyway in Liverpudlian (Scouce). The example below was heard on a bus to Liverpool from two "judies" who were talking.
jessica was at temple one night and described her feelings on her jigger-like self to her rabbi who sat in awe and confusion
also...
jessica-so am i a cheeseburger?
jolo- no i think thats a bad thing or something blah blah blah i like the gators but wear a miami hat blah blah
jess-oh so i must be a jigger