An Etymological Dictionary of Astronomy and Astrophysics

1. Not true or correct; erroneous.
   
2. Not properly, accurately, or honestly made, done, or adjusted.
   → false color, → false dawn, → false nucleus, → false vacuum.

Etymology (EN): From O.Fr. fals, faus, from L. falsus “deceived, erroneous, mistaken,” p.p. of fallere “to deceive, disappoint.”

Etymology (PE): Zif, from Tâleši saf “wrong,” from Mid.Pers. zêfân, zaspân “wrong, vile;” in classical Pers. dictionaries zif “churlishness; sin.”