Kiasuness means: The quality of being kiasu (overly competitive and afraid to lose out).. It is mainly Singaporean English and may not be understood outside that context. It is generally derogatory or offensive; worth a quiet word about how it lands on the person being described. 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.