A sibling or a person who shares a close familial bond, used in informal contexts to refer to a bro or sis.

एक भाई या बहन

English Usage: My sibmating made the family reunion much more enjoyable.

Hindi Usage: मेरी sibmating ने पारिवारिक पुनर्मिलन को और भी आनंदमय बना दिया।

To act in a manner typical of siblings or to develop a sibling-like bond.

भाई-बहन जैसा व्यवहार करना

English Usage: They started sibmating during their college years.

Hindi Usage: वे कॉलेज के वर्षों में भाई-बहन जैसा व्यवहार करने लगे।