The phrase 'in rude health' suggests someone is exceptionally well and implies positivity and strength. Even after a strenuous hike, he appeared in rude health.
Pro Tip 2/3
Informal Usage
'In rude health' is casual and typically used in informal conversations or personal writing. At the family reunion, Grandma was clearly in rude health.
Pro Tip 3/3
Not Literal
Sometimes used figuratively to describe things that are thriving, not just about people's health. The garden was in rude health, with all flowers blooming brightly.