discovered or determined by scientific observation; "variation in the ascertained flux depends on a number of factors"; "the discovered behavior norms"; "discovered differences in achievement"; "no explanation for the observed phenomena"
having once lived or existed or taken place in the real world as distinct from being legendary; "the historical Jesus"; "doubt that a historical Camelot every existed"; "actual historical events"
of or relating to the study of history; "historical scholars"; "a historical perspective"
marked by imagination, initiative, and readiness to undertake new projects; "an enterprising foreign policy"; "an enterprising young man likely to go far"
requiring effort or concentration; complex and not easy to answer or solve; "raised serious objections to the proposal"; "the plan has a serious flaw"
of great consequence; "marriage is a serious matter"
concerned with work or important matters rather than play or trivialities; "a serious student of history"; "a serious attempt to learn to ski"; "gave me a serious look"; "a serious young man"; "are you serious or joking?"; "Don't be so serious!"
clearly characterized or delimited; "lost in a maze of words both defined and undefined"; "each child has clearly defined duties"
clearly defined; "I have no formed opinion about the chances of success"
showing clearly the outline or profile or boundary; "hills defined against the evening sky"; "the setting sun showed the outlined figure of a man standing on the hill"
showing sustained enthusiastic action with unflagging vitality; "an indefatigable advocate of equal rights"; "a tireless worker"; "unflagging pursuit of excellence"
something of value given by one person to another to bind a contract
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"