the last or most difficult challenge or area of exploration
le dernier ou le plus difficile défi ou domaine d'exploration (le dernier ou le plus difficile defi ou domaine d'exploration)
"For many scientists, space remains the final frontier."
"Pour de nombreux scientifiques, l'espace reste la dernière frontière." (Pour de nombreux scientifiques, l'espace reste **la derniere frontiere**.)
to stay composed during difficult times
to start a friendly conversation in an awkward situation
to end a disagreement and become friendly again
to draw attention to something important
to survive a difficult situation
to prepare the body or mind for activity