siccus

Siccus, sicca, siccum, first and second declension. The core sense is plain physical dryness of ground, wood, weather and eyes, and siccis oculis, "with dry eyes", is the standard way of saying someone did not weep.

Two extensions matter. Of a person siccus means sober, one who takes no wine, which gives the pointed contrast in Horace between the dry man and the soaked one. Of prose style it means spare and unadorned, and whether that is praise or an insult depends entirely on who is holding the pen. The verb is sicco, "to dry"; English took desiccate from it, and French sec, Spanish seco and Italian secco are all the adjective walking straight through.