Unwilling to talk; taciturn; refusing to speak(adjective)
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Use "untalkative" in a sentence
"The careful nose, the skin of her there, those careful hands of yours falling around the silent heart, how many, how often in the untalkative water."
"He was one of the first in the field really to see the exceptional virtues and promise of the untalkative young Franklin J.W. Schmidt, who died in a fire just as his work on central Wisconsin prairie chickens was becoming recognized."
"If someone seems overly sullen and untalkative, or nervously preoccupied, that would be a red-flag."