SAT earnest Definition Serious in intention or purpose; showing sincerity. Example "He made an earnest promise to return the borrowed money." Sign in to save SAT PDF — $25 ← eager earring → Study tips featuring "earnest" How Context Clues Save You on the SAT Related words SAT antonym SAT abase SAT abdicate SAT abdomen SAT abduction SAT abet SAT abeyance SAT abject SAT abjure SAT ablution SAT abnegate SAT abnormal