In informal terms the difference between cuz and cus
is that cuz is cousin while cus is because.
As an adverb cuz
is because.
As a noun cuz
is cousin.
cus
English
Conjunction
(head)
(informal) because
----
cuz
English
Etymology 1
Short for because .
Alternative forms
* cause, 'cause, cos, 'cos, coz, 'coz, 'cuz
Adverb
(-)
(informal) because
Etymology 2
Short for cousin .
Noun
(cuzzes)
(informal) cousin