The word "irreplaceable" means that something or someone is so unique or valuable that it would be impossible to find a substitute or replace them. Full definition
Wonderful design, stability, easy access, effective dating services make dating site really irreplaceable for fats search of new friends, lovers and soul mates among single Caribbean men and single women. (loveusadating.com)
It so quickly received vast popularity assisting people to end with their lonely life that became almost irreplaceable part of their life. (date4plus.com)
Of course, many streaming music services like Spotify perform irreplaceable roles in your life by introducing you to new music. (pcmag.com)