Habis means: To finish or be finished; used to express that something is over or cannot be undone.. It is mainly Singaporean English and may not be understood outside that context. It has drug-related associations; worth a calm conversation about which side of the topic your teen is on. 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.