na-BAY-woort
If you know IPA [ nabeiwuɖ ]

na- is the male noun class prefix
beywurd 'child of patriline'
wurd is formative in wurdyaw 'child' and wurdurd 'children'

To learn more about noun class prefixes, read the blog post at:
http://bininjgunwok.org.au/2012/classes-of-nouns/

nabeywurd is how other people designate the son of a man or a woman's brother's son. These are not terms of address (vocative terms). A man says 'korlonj' to their son or daughter, as does a woman to their brother's children.

In Gundjeihmi this word would be spelt nabeiwurd (pronunciation is the same).

Nabeywurd bibornang. 'He had a son'

Na-beywurd
male-child.of.patriline
bi -borna -ng
he>him -father_a_child -past_tense

He fathered a son.

Note that you can also say this of a woman in relation to their brother's son.
Nabeywurd bibornang 'she "fathered" a child [i.e. her brother's son]'. Your father's sister is like a female "father" and your mother's brother is like a male "mother".