Definition of "good day"

good day

phrase
1. (dated, formal) A somewhat formal greeting generally used between sunrise and sunset.
  Quotations
  Good day, and happineſſe, deere Roſalind.
  c. 1598–1600 (date written), William Shakespeare, “As You Like It”, in Mr. William Shakespeares Comedies, Histories, & Tragedies […] (First Folio), London: […] Isaac Iaggard, and Ed[ward] Blount, published 1623, [Act IV, scene i], page 200
2. (dated, formal) A dismissal; sometimes used to express annoyance.
  Quotations
  This is an invitation-only party! Now, good day!
  2012, Mike Cerrone, Bobby & Peter Farrelly, The Three Stooges (motion picture), spoken by Carbunkle (Ray Collins)