It surprises me how often people are criticised for “contemplating their naval”. I’ve seen this usage several times recently.
You can’t “contemplate your naval” unless, perhaps, you’re an admiral contemplating your naval strategy or something of the kind. But no one can contemplate a “naval” – for the simple reason that there is no such thing.
They mean navel.
Your navel is your umbilicus to give it its clinical term, or belly button in common parlance. It comes from an Old English and Germanic word meaning the middle of a thing. The word nave, meaning the central part of a church building, comes from the same root.
Navel-gazing in its true and original sense refers to the contemplation of one’s navel as an aid to meditation, an esoteric practice that has been adopted in many cultures including in Hinduism and in the Eastern Orthodox Church, I read. But in everyday speech the term is more likely to be used in a negative sense to signify useless or excessive self-contemplation, or inaction.
There is also a kind of orange called a navel orange, characterised by the growth of a second, small fruit at its apex, which is said to give it the appearance of a human navel.
Naval means “of or relating to the navy”, as in a naval officer or naval strategy.
You can read about the difference between navel and naval and a whole lot more, in the Clifford & Co editorial style guide.