Dictionary:

acetous

  (ə-sē'təs, ăs'ĭ-təs)

1. Of, relating to, or producing acetic acid or vinegar.
2. Having an acetic taste; sour-tasting.

[Middle English, sour, from Medieval Latin acētōsus, vinegary, from Latin acētum, vinegar. See acetum.]

adjective

Having a taste characteristic of that produced by acids: acerb, acerbic, acid, acidulous, dry, sour, tangy, tart. See taste/bad taste.

The adjective has one meaning:

Meaning #1: tasting like vinegar
  Synonyms: acetose, vinegary