Noun: A person with no clue of how to do anything. A bumbling idiot. Usually loved and adored by other bumblefucks, thus creating a colony of bumblefucks.
Bumblefuck Queen: Lawdy, I've just been elected as your class president, and my first act will be to move prom to Popeyes and make No hands our class song.
A reasonable person: How did a bumblefuck like you get elected? Oh right, you guys swarm together.
A person who goes through their life very similarly to how a bumblebee flies- slow, clumsy, and troubled. Aerodynamically impossible, but somehow they manage.
They can be well-meaning jackasses who make stupid mistakes, or complete idiots who have no idea what they're doing, but continue to pursue their dreams of pollination. Sometimes they're endearing- it takes all types.
You don't want them near delicate objects, or within 50 feet of a china shop.
Bill, that bumblefuck, ended up burning the eyebrowsoff his face with a blowtorch last Tuesday in effort to make an ice sculpture for a girl he loved.
Nancy, head bumblefuck of the local high school district, invested a large percentage of the school's money in stocks that failed.