Bumpy means full of small rises and dips. A bumpy road, a bumpy flight, bumpy ground.
Of a surface it means uneven enough to feel through a wheel or a foot. Of a flight it is the polite word for turbulence, and cabin crew use it precisely because it sounds mild. Figuratively, a bumpy ride means a difficult period with recoveries in it, which is why it suits a career or a share price better than a disaster. Note bump, bumpiness.
1adjectivebumpyFull of small rises and dips.
“The bus bounced along the bumpy country road, and my coffee spilt everywhere.”
2adjectiveturbulentTurbulent, of a flight.
“The pilot warned us that the flight would be bumpy as we crossed the mountains.”
bumpy is a quality of unevenness.
From bump + -y.
Etymology from Wiktionary, CC BY-SA