Long ago, when the doughnut was invented, the entirety of planet Earth rejoiced at the delicious iced pastry, until one day, somebody pointed out that it contained the word "ugh", which is commonly associated with horror and dismay. This eventually led to "doughnut" being shortened to "donut", all for the better. A bagel is a lesser donut. It effectively puts the "ugh" back in "doughnut" and should be avoided at all costs if a donut is available.

the male private part

exclamation concerning something related to splendor or pleasure

A woman with an extremely worn, stretched out vagina.

plain donut, only good if it has stuff on it

something you shove your dick in when you have nothing else

Someone who is extremely cheap.

(Comes from the generic Jew characteristic of frugal, and the fact that all Jews love bagels)