4
nonexistent(adjective, nonexistent)
4
perplexed
4
scatterbrained(adjective, simple, slow, stupid, boring)
4
simple(adjective, dull, slow, foolish, stupid)
4
uncomprehending(adjective, empty, unintelligent)
4
unintelligent(adjective, simple, slow, indifferent, silly)
4
unmindful(adjective, obtuse, unperceptive, unobservant)
4
unreasonable(adjective, careless, stupid, thoughtless, absurd)
4
unreasoning(adjective, careless, stupid, empty, unthinking)
3
absent(adjective, usual, deficient, incogitancy)
3
absurd
3
astonished
3
bewildered
3
brainless(adjective, dull, simple, slow, stupid)
3
characterless(adjective, dreary, monotonous, uninteresting, unlively)
3
daft(adjective, simple, slow, silly, stupid)
3
dense(adjective, dull, simple, slow, stupid)
3
drained(adjective, clear, free, stupid, empty)
3
forgetful
3
glassy
11 years ago|15k views|share |citing 
APASmart Define. (2015). vacuous thesaurus. Retrieved September 20, 2026, from https://smartdefine.org/vacuous/thesaurus/synonyms
ChicagoSmart Define. 2015. "vacuous thesaurus" https://smartdefine.org/vacuous/thesaurus/synonyms (accessed September 20, 2026).
HarvardSmart Define 2015, vacuous thesaurus, Smart Define, viewed 20 September, 2026, <https://smartdefine.org/vacuous/thesaurus/synonyms>.
MLASmart Define. "vacuous thesaurus" 10 April 2015. Web. 20 September 2026. <https://smartdefine.org/vacuous/thesaurus/synonyms>