to let up

from The Collaborative International Dictionary of English v.0.48

Let \Let\, v. i.
   1. To forbear. [Obs.] --Bacon.
      [1913 Webster]

   2. To be let or leased; as, the farm lets for $500 a year.
      See note under {Let}, v. t.
      [1913 Webster]

   {To let on}, to tell; to tattle; to divulge something. [Low]
      

   {To let up}, to become less severe; to diminish; to cease;
      as, when the storm lets up. [Colloq.]
      [1913 Webster]