Synonyms of earnest

1. earnest, security, surety: usage: something of value given by one person to another to bind a contract

1. earnest, sincere, solemn, serious (vs. frivolous): usage: characterized by a firm and humorless belief in the validity of your opinions; "both sides were deeply in earnest, even passionate"; "an entirely sincere and cruel tyrant"; "a film with a solemn social message"
2. dear, devout, earnest, heartfelt, sincere (vs. insincere): usage: earnest; "one's dearest wish"; "devout wishes for their success"; "heartfelt condolences"
3. businesslike, earnest, purposeful (vs. purposeless): usage: not distracted by anything unrelated to the goal