A small, circular hand blade used to cut a perfectly round piece of wrapper leaf for capping the head of a cigar.
Why it matters
A clean chupi cut is what lets a cap sit flush with no visible seam gap, which is a large part of what separates a tidy factory finish from a rough one.
In context
"The roller punched a disc from the wrapper scrap with the chupi and set it aside for the cap."