(archaic) Master workman; overseer; employer of workmen.
1703, Richard Neve (pseudonym T. N. Philomath), The City and Countrey Purchaser, and Builder’s Dictionary, London: J. Sprint et al., title page,
The Customs, and Methods of Measuring of all Artificers Work, concern’d in Building; together with the City and Countrey Prices, not only of Workmanship, but of Materials also: The which will be extraordinary useful in making of Bargains, or Contracts betwixt the Workmaster and Workman; and likewise in computing the Value (or Charge of Erecting) of any Fabrick, great or small.