i Register
In some senses, coz is marked as informal. Watch for register when choosing this word.
noun
cousin (usually as a term of address)
Content thee, gentle coz, let him alone.
1844, Elizabeth Oakes Smith, "The Love Quarrel", in The Columbian Magazine Vol 1. Issue 1. page 6, col. 2, New York, Israel Post, ed John Inman "I do not expect that, coz; nor do I desire it."
conj
Informal spelling of 'cause (“because”).