(ûr′nist) adjective
1. Intent and direct in purpose; zealous; fervent: of persons.
2. Marked by deep feeling or conviction; heart-felt; hearty: of words or acts.
3. Requiring careful consideration; serious; important. See synonyms under EAGER, SERIOUS.
—noun Seriousness; reality, as opposed to pretense or trifling.
—in earnest With full and serious intent; real and intended. [OE eorneste]
—ear′nest·ly adverb
—ear′nest·ness noun

(ûr′nist) noun
1. Money paid in advance to bind a bargain.
2. An assurance of something to come; pledge. See synonyms under SECURITY. [Prob. <OF erres <L arra, arrhabo <Gk. arrhabōn1 <Hebrew ‘ērābōn; infl. by EARNEST¹]