The term 'spring up' can be described by the crossword solutions of 'BOUNCE, ' 'SPROUT, ' 'LEAP, ' 'GROW, ' 'ARISE, ' 'RISE, ' and 'START.' These words all describe the action of quickly coming into existence or activity, as if something is springing up. For example, when something bounces, it quickly jumps up from a surface. When something sprouts, it quickly grows from a seed. When something leaps, it quickly jumps up from the ground. When something grows, it quickly increases in size. When something arises, it quickly comes into being. When something rises, it quickly moves upward. Finally, when something starts, it quickly begins.