Obsolete form of earnest.
"The old manuscript used the obsolete spelling ernest to denote an earnest intention before modern dictionaries standardized the term."
A male given name from the Germanic languages; popular in the 19th century.
"Ernest was a popular choice for baby boys during the Victorian era, reflecting its roots as a Germanic given name."
Borrowed in the 18th century from Ernst, a medieval royal name in Germany, from Old High German ernust ("vigor, strife"), only remotely related to modern German ernst or English earnest.