He realized his blockhead mistake too late to fix it.
blockhead move
Frequency:
70
%
It was a blockhead move to trust him with the secret.
blockhead decision
Frequency:
60
%
Making such a blockhead decision cost them the game.
blockhead behavior
Frequency:
50
%
His blockhead behavior at the party embarrassed his friends.
Idiomatic Expressions for blockhead
Phrase: He's a real blockhead
Meaning: He's a foolish or stupid person
Usage: Used to describe someone who is not very intelligent or makes poor decisions