Definition of "slacken" [slack•en]

• To make or become slower; slow down: The runners slackened their pace. Air speed slackened. (verb-transitive)
• To make or become less tense, taut, or firm; loosen: I slackened the line to let the fish swim. The tension in the board room finally slackened. (verb-transitive)
• To make or become less vigorous, intense, or severe; ease: slacken discipline; afraid that morale might slacken. (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.

• "Think I’ll just kind of slacken up on this G.C.L. stuff now."
• "Think I'll just kind of slacken up on this G.C.L. stuff now. ''"
• "No matter which of the two levers he clicked below either hand-grip, the chain seemed to slacken, meaning the pedals spun faster, and the bike slowed."