Third-person singular simple present indicative form of tighten.(verb)
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Use "tightens" in a sentence
"Historically, the Kremlin tightens media and societal controls before elections."
"His skin tightens as the February air pours in around him, but he isn't troubled by the cold."
"Although some people see results immediately, the results get better over a three to six month time period, as new collagen is formed and the skin tightens."