The project was a total disaster due to his dumbassery.
sheer stupidity
Frequency:
55
%
The decision was met with sheer stupidity.
utter nonsense
Frequency:
50
%
The excuse he gave was utter nonsense.
complete idiocy
Frequency:
45
%
His actions were a display of complete idiocy.
Idiomatic Expressions for dumbassery
Phrase: engage in dumbassery
Meaning: to participate in foolish or senseless actions
Usage: She decided to engage in dumbassery by attempting to climb the tree after being warned it was unsafe.