sal

Sal, salis is third declension, usually masculine in the singular and neuter in some older writers, which is the sort of wobble a very old word is allowed. The plural sales is masculine and means witticisms, not grains of salt.

That second sense is the useful one. Roman writers treat salt as the metaphor for sharpness in speech, so a man with sal is funny and pointed, and sine sale is dull; English inherited exactly this in "salty" and in the phrase "the salt of the earth", which arrives via the Vulgate line above. The word also stands behind salarium, the salt allowance paid to soldiers, and therefore behind English salary, salad, sauce and sausage.