Definition of "tighten" []

• To make or become tight or tighter. (verb-transitive)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "I can’t, she thought, watching his expression tighten with anger."
• "Otis saw the youngster's expression tighten and knew it had nothing to do with the difficulties of the game."
• "We winos are having to tighten, which is to say loosen, our belts."