| resistant(adjective, strong, hard, sound, tough) |
| roaring(strong, tough, healthy, well) |
| robustious(strong, tough, healthy, well) |
| robustuous(strong, tough, healthy, well) |
| seasoned(adjective, strong, hard, sound, tough) |
| snappy(strong, tough, healthy, well) |
| tenacious(strong, determined, vigorous, healthy) |
| thriving(strong, tough, healthy, well) |
| tiger(strong, tough, vigorous, healthy) |
| unflagging(strong, healthy, well, robust) |
| well(strong, tough, healthy, robust) |
| wicked(strong, tough, healthy, well) |
| zappy(strong, tough, healthy, well) |
| zippy(strong, tough, healthy, well) |
| acclimatized(strong, healthy, well, robust) |
| active |
| agile |
| hale and hearty(expression, idiom, healthy, well) |
| inured(strong, healthy, well, robust) |
| lithe |