Detailed description and alternate definitions of the word 'blunder':

To make a stupid, usually serious error in; botch.

To utter (something) stupidly or thoughtlessly.

A usually serious mistake typically caused by ignorance or confusion.

To make a usually serious mistake.

To move clumsily or blindly.
Synonyms of word 'blunder' :

goof

foul-up

sin

flub

botch

blooper

blurt out

ejaculate

fuckup

boo-boo

blunder out

blurt

boob

bloomer

pratfall

bungle

drop the ball

fumble

boner