Learner's definition of BUMPY
[or more bumpy; most bumpy]
1 of a surface : having or covered with bumps 2 : having sudden up and down movements 3 : having a lot of problems
a bumpy relationship
The project got off to a bumpy [=rocky] start, but it's back on schedule now.
Production of the movie has been a bumpy ride. [=there have been a lot of problems during the production of the movie]