Serious blunder (7)
I believe the answer is:
clanger
(Other definitions for clanger that I've seen before include "Stupid mistake" , "Bell possibly" , "Big blunder" , "Big mistake (when dropped)" , "noise that rings in the ear" .)
I believe the answer is:
clanger
(Other definitions for clanger that I've seen before include "Stupid mistake" , "Bell possibly" , "Big blunder" , "Big mistake (when dropped)" , "noise that rings in the ear" .)