Someone clumsy is a klutz. They're awkward, ungraceful, and walk like they have two left feet. Something hard to handle — like a huge box — is also clumsy.
A badly told story is told in a clumsy way, and a couch that's hard to move clumsy to carry. But mostly being clumsy is embarrassing. Dropping things, tripping a lot, and stumbling are all examples of clumsiness. Clumsy people usually aren't too good at sports or dancing. And you certainly don't want a clumsy surgeon. Most people are a little clumsy when they're teenagers — growing so fast makes it hard to be sure of yourself physically.