The Collaborative International Dictionary of English v.0.48:

Leaser \Leas"er\, n. [From 1st Lease.]
   One who leases or gleans. [Obs.] --Swift.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Leaser \Leas"er\, n.
   A liar. [Obs.] See Leasing.
   [1913 Webster]