The Collaborative International Dictionary of English v.0.48:

Laird \Laird\ (l[^a]rd), n. [See Lord.]
   A lord; a landholder, esp. one who holds land directly of the
   crown. [Scot.]
   [1913 Webster]

WordNet (r) 3.0 (2006):

laird
    n 1: a landowner

Moby Thesaurus II by Grady Ward, 1.0:

60 Moby Thesaurus words for "laird":
   Brahman, archduke, aristocrat, armiger, baron, baronet,
   beneficiary, blue blood, cestui, cestui que trust, cestui que use,
   count, daimio, deedholder, duke, earl, esquire, feoffee, feudatory,
   gentleman, grand duke, grandee, hidalgo, householder, lace-curtain,
   landgrave, landlady, landlord, lord, lordling, magnate, magnifico,
   margrave, marquis, master, mesne, mesne lord, mistress, noble,
   nobleman, optimate, owner, palsgrave, patrician, peer, proprietary,
   proprietor, proprietress, proprietrix, rentier, seigneur, seignior,
   silk-stocking, squire, swell, thoroughbred, titleholder,
   upper-cruster, viscount, waldgrave