The word "wert up to" can be interpreted as reaching a certain standard or expectation. Antonyms for this phrase include falling short or failing to meet expectations. Other antonyms could include being mediocre, unimpressive or insufficient. Words like "inferior," "substandard," or "unsatisfactory" are good antonyms for "wert up to." Additionally, words like "deficient," "incomplete," or "unaccomplished" could also work as antonyms. Ultimately, when someone says that something wasn't "wert up to" what they expected or wanted, they could be indicating that they felt let down, disappointed, or dissatisfied. So, choosing the right antonym to describe this feeling can be crucial to communicating what exactly went wrong.