sister

Example:It’s a tradition that every brother should support his younger sibling when they face difficulty.

Definition:A male person who is a sibling, i.e., having the same mother and father (or at least the same mother) as another person.

Example:He cautiously communicated with the stranger and shared only basic details of himself.

Definition:A person who is not known to another person; a stranger to someone is not familiar or acquainted with that person.