Underseasoned means not given enough salt or spice. An underseasoned soup, slightly underseasoned, underseasoned throughout.
It is the commonest fault in home cooking and the easiest to fix, since salt can be added at the end and never taken out. Chefs season in layers as they cook rather than once at the finish.
1adjectiveunderseasonedNot given enough salt or spice.
“The soup was underseasoned, so she added more salt and a little pepper.”
underseasoned is a quality.
Under plus seasoned, from season in the sense of flavouring food.
From under + seasoned.
Etymology from Wiktionary, CC BY-SA