This word is quite interesting. It refers to a female ninja.
Meaning: female ninja
I am not sure but I heard that this is the only word in Japanese that uses all three writing systems in one word. The first letter is the hiragana 'ku' letter. The second one is the katakana 'no' letter and the last one is the Kanji symbol for 'one'.
Another interesting thing is that this word, although it doesn't seem so, does represent a woman! To find out you simply need to draw all three letters at the same location. If you draw く, ノ, and then 一 at the same location, you get... 女, which is the Kanji symbol for 'woman'. Isn't that cool?
Being a ninja, the woman disguises herself...
I also know this is how children in school learn how to draw the 女 symbol.