The given name Jeniffer is a variant spelling of the name Jennifer, which has its origins in the ancient Celtic language of Brittonic. The name is derived from the Welsh feminine name Gwenhwyfar, which translates to "the fair or white enchantress."

The earliest known record of the name Gwenhwyfar dates back to the 6th century AD. It was used in medieval Welsh literature, such as the Arthurian legends, where it was the name of King Arthur's wife. The name Gwenhwyfar evolved into various spellings, including Guenevere, Guanhumara, and eventually Jennifer.

In the 12th century, the name Jennifer was introduced into English through the Norman-French form Genieure. Over time, the spelling evolved into Jennifer, which became a popular name in the English-speaking world. The earliest recorded use of the spelling Jennifer in English dates back to the 16th century.

One of the earliest known historical figures with the name Jennifer was Jennifer Duval, a French noblewoman who lived in the 16th century. Another notable Jennifer from history was Jennifer Vashon, an English actress and singer from the 17th century, born in 1630 and died in 1703.

In the 19th century, Jennifer Hogg was a Scottish writer and educator, born in 1824 and died in 1900. Jennifer Rowley, an American soprano singer, was born in 1930 and had a successful career in opera performances during the 20th century.

One of the most famous Jennifers in modern times was Jennifer Jones, an American actress who was born in 1919 and died in 1976. She won the Academy Award for Best Actress for her role in the 1943 film "The Song of Bernadette."