The Collaborative International Dictionary of English v.0.48:

Pert \Pert\, v. i.
   To behave with pertness. [Obs.] --Gauden.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Pert \Pert\, a. [An aphetic form of OE. & OF. apert open, known,
   true, free, or impudent. See Apert.]
   1. Open; evident; apert. [Obs.] --Piers Plowman.
      [1913 Webster]

   2. Lively; brisk; sprightly; smart. [Obs.] --Shak.
      [1913 Webster]

   3. Indecorously free, or presuming; saucy; bold; impertinent.
      "A very pert manner." --Addison.
      [1913 Webster]

            The squirrel, flippant, pert, and full of play.
                                                  --Cowper.
      [1913 Webster]

WordNet (r) 3.0 (2006):

pert
    adj 1: characterized by a lightly pert and exuberant quality; "a
           certain irreverent gaiety and ease of manner" [syn:
           impertinent, irreverent, pert, saucy]

The Free On-line Dictionary of Computing (19 January 2023):

Program Evaluation and Review Technique
PERT

    (PERT) A method used to size a software product
   and calculate the Standard Deviation (SD) for risk assessment.
   The PERT equation (beta distribution) estimates the Equivalent
   Delivered Source Instructions (EDSIs) and the SD based on
   the analyst's estimates of the lowest possible size, the most
   likely size, and the highest possible size of each computer
   program component (CPC).

   (1996-05-29)