fifth son
Used in family contexts to refer to the fifth-born son. Often appears in formal or written descriptions of family composition.
He is the fifth son and the youngest among his siblings.
Refers to the eldest son, in contrast to 五男 which specifically means the fifth son.
Refers to the second son, while 五男 is the fifth son.
Compound of 五 (go, 'five') and 男 (nan, 'male' or 'son'). The reading ごなん follows standard on'yomi.