Lewis & Short

praesumptor, ōris, m. [praesumo].

  1. I. One who takes possession beforehand, a preoccupier (post-class.), Cassiod. Var. 1, 18.
  2. II. A bold, confident, reckless, or presumptuous person, Tert. Poen. 6: Petrus ex egregio praesumptore tam creber negator effectus, Aug. Ep. 120, c. 14; Hier. Ep. 89: praesumptor (Adam) senserit iram meritam, Sedul. 2, 4; cf. Cod. Th. 16, 2, 48: Leo, Ep. 10, 9.