As a verb bun
is to be.
As a proper noun abun is
a language, sometimes considered an isolate and sometimes considered west papuan, spoken in papua and divided into the dialects abun tat (karon pantai), abun ji (madik) and abun je.
As a noun abun is
father, (the title of a bishop in an ethiopian or coptic church
Other Comparisons: What's the difference?
A small bread roll, often sweetened or spiced.
A tight roll of hair worn at the back of the head.
(Ireland) A cupcake.
(slang, British) A drunken spree.
(Internet, slang) A newbie.
(dialect, obsolete) A squirrel or rabbit.
* (hairstyle) French roll
* bun fight
* bun stock
* Chelsea bun
* currant bun
* have a bun in the oven
* hot cross bun
(UK, slang) To smoke cannabis.