Source : Webster's Revised Unabridged Dictionary (1913)

   {To let} {drive or fly}, to discharge with violence, as a
      blow, an arrow, or stone. See under {Drive}, and {Fly}.

   {To let in} or into.
      (a) To permit or suffer to enter; to admit.
      (b) To insert, or imbed, as a piece of wood, in a recess
          formed in a surface for the purpose. {To let loose},
      to remove restraint from; to permit to wander at large.

   {To let off.}
      (a) To discharge; to let fly, as an arrow; to fire the
          charge of, as a gun.
      (b) To release, as from an engagement or obligation.
          [Colloq.]

   {To let out}.
      (a) To allow to go forth; as, to let out a prisoner.
      (b) To extend or loosen, as the folds of a garment; to
          enlarge; to suffer to run out, as a cord.
      (c) To lease; to give out for performance by contract, as
          a job.
      (d) To divulge.

   {To let slide}, to let go; to cease to care for. [Colloq.] ``
      Let the world slide.'' --Shak.