Informal. a blunderer; nincompoop.
Origin of blunderhead
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
Examples from the Web for blunderhead
Historical Examples of blunderhead
What were ye thinking of, Alvin, to let such a blunderhead manage yer craft?The Launch Boys' Cruise in the Deerfoot
Edward S. Ellis