“Kicked the bucket” is a lighthearted way of expressing that someone has died. Saying “passed away” communicates the same information but in a more tactful and sensitive manner. These diplomatic expressions are called euphemisms, and speakers and writers use them in place of literal phrases to express sensitive, somber, taboo or embarrassing topics in a less offensive way.
A euphemism sometimes originates as an idiomatic expression whose literal meaning has been lost. For example, “kicked the bucket” might refer to the buckets from which slaughtered pigs were hung in East Anglia. This expression has taken on the meaning “died,” even though the original reference to pig slaughtering has been forgotten. Other times euphemisms may take the form of a technical term, such as “civilian casualties” instead of "deaths" or "murders."
The word “euphemism” derives from the Greek word “euphemismos,” which denotes using more pleasant words in place of unfavorable or discouraging ones. “Eu” in Greek means “good,” while “pheme” means “to speak.” Euphemism is the opposite of “dysphemism,” which means to say something offensive in place of a more neutral term, such as “tramp” instead of “a promiscuous person.” The prefix “dys” expresses “bad” or “abnormal.”
Euphemisms sometimes depend on the social context of the speaker or writer. For example, at a social gathering, one might ask the location of the “ladies' room” or “powder room,” instead of “toilet.” Society has used various terms throughout history to denote that a woman is pregnant. The King James Bible referred to pregnancy as "being with child." Victorians described pregnant women as having "a delicate condition." In the 20th and 21st centuries, euphemisms for pregnant women have not been so kind: "knocked up," "up the duff" and "bun in the oven" are a few humorous examples you might hear on a sitcom. Writers of literature must consider the social contexts of their characters to use euphemisms in a believable manner.
Shakespeare’s plays teem with euphemisms, especially when referring to sex, such as when Iago tells Brabantio in “Othello” that his daughter and the Moor “are now making the beast with two backs.” The euphemism “ruin” to describe a woman’s loss of eligibility of marriage due to premarital sexual exploits of any kind (even only perceived exploits) is common in Victorian novels such as those by Jane Austen, Elizabeth Gaskell, the Bronte sisters and Charles Dickens.