LENTS'WORLD:
virulent Look up virulent at Dictionary.com
1400, in ref. to wounds, ulcers, etc., "full of corrupt or poisonous matter," from L. virulentus "poisonous," from virus "poison" (see virus). Fig. sense of "violent, spiteful" is attested from 1607.

TRUCULENT: sullen and ready for a fight

Compare PUGNACIOUS, which describes a person who's looking for a fight

If a pugnacious person is orange, a truculent one is brick.
If a pugnacious person is red, a truculent one is purple.
Let's reserve violet for the actively violent.

Now compare TRUCULENT with SUCCULENT, which basically means "wet inside."

A person with a FECULENT attitude may be considered truculent, but feculence has nothing to do with succulence. Those of you who have stepped in a fresh cow patty while barefoot might disagree, but that's my story and I'm sticking to it.