the GNU version of the Collaborative International Dictionary of English
adj. Without understanding; silly; thoughtless; witless.
The Century Dictionary and Cyclopedia
Weak in the brain; witless; stupid: as, “the dull brainless Ajax,”
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
adj. not using intelligence
Word Usage
"The entire film is an exaggerated study in brainless women being used for decorative purposes, but it's so damn lousy that I can't even muster up any reactionary feminist offense to it."