in earnest serious or seriously; sincere or sincerely At seventy-seven it is time to be in earnest — Dr Johnson [Old English eornost]
something of value, esp money, given by a buyer to a seller to seal a bargaina token of what is to come; a pledge [Middle English ernes, ernest, from Old French erres, pl of erre pledge, via Latin and Greek from Hebrew ‘ērābhōn]