"Significant achievement" means a noteworthy or important accomplishment. It refers to something that is notable, impressive, and has a significant impact or value. Full definition
This special award acknowledges a scientist who is under the age of 50 years, for significant achievements in the field of nutrition. (hopkinsmedicine.org)
Proven record of significant achievements for the benefit of the best industry players. (members.climber.com)
Whatever the eventual prize is one thing's for certain: whoever managed to crack that last cube will have unlocked a most significant achievement in gaming history. (plusxp.com)