Spanish for turnip, which in Gibraltar at least can be used to mean dick. Correct spelling is nabo.

when you're hungover as shit after a spending a night drunk as a skunk

Another word for a badass, Navo is a top preforming vocalist who can come up with insults on the fly, and is also very loud in general. Navo is commonly used in jokes, reffering to someone who can talk fast and say funny insults in quick time.