Expressionless is a related term of vacuous.
As adjectives the difference between expressionless and vacuous
is that expressionless is without expression while vacuous is lacking meaningful content.
vacuous
English
Adjective
(
en adjective)
Lacking meaningful content.
Showing a lack of thought or intelligence; vacant
Derived terms
* vacuity (noun)
* vacuously (adverb)
* vacuousness (noun)