Original: In the close approach that led to its initial discovery, not enough observations could be made to calculate an orbit, and Adonis was a lost asteroid until 1977 when it was rediscovered by Charles T. Kowal.
Simplified: In the close approach that led to the first time it was found, not enough sightings could be made to find out it's orbit, and Adonis was lost until 1977 when it was found once again by Charles T. Kowal.