It's possible that:
* It's a misspelling or variation of another word. Check for similar spellings or variations, like "kiihuu" or "kiiru".
* It's a regional or dialectal term. The word might be used in a specific region or among a particular group of Kikuyu speakers.
* It's a new word. Languages are constantly evolving, and new words can emerge.
To get a clearer understanding, you'll need to provide more context:
* Where did you hear or see this word?
* What was the situation?
* What was the speaker trying to convey?
With more information, we can potentially figure out the meaning of "kiihu".