The RaMBaM wrote:
A father [has the right to] nullify any vows and oaths [taken by his daughter only] on the day he hears of them, as [Numbers 30:6] states: “[But if her father withheld her on the day that he heard,] all of her vows and prohibitions… [shall not stand].”
There’s a general idea that making a neder is like building a bama, an altar, and not nullifying your neder, or petitioning for a nullification, is like offering a korban on the bama. Both of these would be major sins for almost all of Jewish history since Sinai, but the metaphor still works because we can picture it visually and use it as a parable to understand our own minds, and statements, as potentially altar-like. Our goal bzmanenu is to transfer that energy to learning and davening, I would think.
But still the plain meaning is that it is a term for “withholding” and “removing” (and the word והפר only shows how and by what means she is to be withheld from keeping her vow); and similar is (Numbers 32:7): “And wherefore do you remove (תניאון) [the heart of the children of Israel from the idea of passing over the land]”; and so, too, (Psalms 141:5): “Oil so choice, let not my head turn away (יניא), and similar, also, (Numbers 14:34): “And ye shall know My turning aside (תנואתי)” — i.e. ye shall know that ye have turned aside from Me.
Before learning Nedarim in daf yomi, I did not consider my own nedarim as closely as I do now. The main value of making a neder against nedarim, if such a thing is possible, is that it frees you having to predict the future, which, of course, we can’t personally do. Through prophecy certain people in history had the power to warn the people against sinning. Otherwise, we almost never can reliably predict the future. And what a relief that is!