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Webster 1828 Edition

ppr.

Tripping; erring; puzzling.

stumbling

stumbling ‎(plural stumblings)

The motion of one who stumbles.
- 2008 March 16, Alexander Star, “I Feel Good”, in New York Times:
  Some evolutionary theorists stress that cultural innovation allows human beings to overcome the blind stumblings of natural selection: we deliberately solve a problem and pass on that solution to our descendants, who improve on it in turn.