Bungler (n.)

1. Bungler (n.): Someone who makes mistakes because of incompetence. A clumsy person.
-His mom did not let Jared carry the turkey to the table on Thanksgiving because he had a reputation for being a major bungler.

Bumptious (adj.)

1. Bumptious (adj.): Arrogant.
-To many, Steve Jobs was bumptious to not consider Android a threat in the mobile industry.