What's the adjective for expressionlessness? Here's the word you're looking for.
Included below are past participle and present participle forms for the
verbs express and expresse which may be used as adjectives within certain contexts.
express
(not comparable) Moving or operating quickly, as a train not making local stops.
“Stella cradled the toy to her, an expressive look on her face.”
“Listeners prefer the expressive music produced by humans, likely because these performances have the subtle variations typical of human expressiveness.”
“Of all the journalistic stereotypes regularly committed to celluloid, none has been more expressive of its times than the war correspondent.”