It's important to understand that Setswana, like many other languages, has a lot of slang and colloquialisms. "Koko" might have different meanings depending on the context and the speaker's intention.
Possible meanings:
* Affectionate Term: It could be used as an affectionate term, similar to "honey" or "sweetheart."
* Informal Greeting: In some instances, it could be used as a casual greeting, similar to "hey" or "what's up."
* Expletive: It could also be used as a mild expletive, expressing surprise or annoyance.
To understand the meaning of "koko" in a particular situation, you would need more context. For example:
* Who is saying it? Is it a friend, a family member, a stranger?
* What is the tone of voice? Is it playful, serious, angry?
* What is the situation? Are they having a conversation, arguing, or just saying hello?
Without more information, it's difficult to pinpoint the precise meaning of "koko."