A male given name from the Germanic languages, the usual U.S. spelling of Geoffrey. Popular in the latter half of the 20th century.
"Jeffrey is a common male given name that became popular in the United States during the mid-1900s as an alternative to the traditional spelling Geoffrey."
Jeffrey is a variant spelling of the name Geoffrey that entered English usage as an alternative form. It shares its Germanic origins and core meaning with its parent name but was adopted independently to provide a distinct written version.