A Sentient or Sapient being. Particularly one which travels amongst and colonizes star systems. It's root suggests the word means: beings with the ability to communicate creatively, ala Sophistry.
The Vargr pirate barked an objection at the notion that prey species, such as the K'kree, qualified as Sophant beings...never mind that they colonized numerous worlds.
misspelling of sophont
Hecateus spells sophont as sophant, making me wonder if he's actually read the Traveller rules where it originates.