Woobie means: A fictional character, often morally grey or a villain, subjected to constant stress and angst, so as to create pathos within the narrative and increase the reader/viewer's emotional attachment to. There is no real cause for parental concern; it is descriptive vocabulary rather than risky behaviour. If your teen uses it, context will usually make the intent clear. A short, curious question about where they heard it is usually all that is needed to know whether to follow up.