2. To be remiss or backward; to be negligent.
3. To lose cohesion or solidity by a chemical combination
with water; to slake; as, lime slacks.
4. To abate; to become less violent.
Whence these raging fires Will slacken, if his
breath stir not their flames. --Milton.
5. To lose rapidity; to become more slow; as, a current of
water slackens.
6. To languish; to fail; to flag.
7. To end; to cease; to desist; to slake. [Obs.]
That through your death your lineage should slack.
--Chaucer.
They will not of that firste purpose slack.
--Chaucer.