"Negligible" roughly means "Small enough to essentially be zero." For example, in high school physics problems, air resistance is negligible. Is there a word that means "large enough to be essentially infinite"? For example, "For someone on a bike, the distance to the other side of the world is ______."
Are you looking for "immensurable" or "immeasurable"?
immensurable (adj) immeasurable, impossible to measure TFD
- "He was a man who displayed immensurable courage even in the face of overwhelming adversity."
- "The immensurable magnitude of some stars."
- "Its applicability is immensurable."
I would say it's substantial.
1. Considerable in importance, value, degree, amount, or extent:
(Note that you could go with considerable itself as well.)
Does a dog have the Buddha nature? Unfortunately, your question has some logical fallacies.
"Small enough to essentially be zero" is the definition of infinitesimal, not negligible. When dividing by zero, or a number close to zero, for example, the result is certainly not negligible, so defining negligible with the word zero is a mistake.
A better (but still truncated) definition is something like "so small as to warrant little or no attention." The opposite of that definition is "so large as to warrant attention," which is the definition of significant.
A second problem is that the opposite of infinite (immeasurable) is finite (measurable), not zero. So attempting to oppose zero and infinite is an unfortunate side-effect of attempting to simplify your definition of negligible.
Conclusion: in the context of measurement, the antonym of negligible is significant.
One could in many cases use prohibitive.
- sufficing to prevent the use, purchase, etc., of something
[ie sufficiently high (often of prices), large ...]
Insurmountable is one option, if you mean to say that it is impossible for the person to bike that distance (some may be able to).
For a more aggressive tone, unassailable also works.
Also overwhelming or insuperable.
The word 'negligible' means insignificant, paltry.
His resources were neglible and so he could not attend college.
The opposite would be 'not neglible,' which would be something akin to
"considerable" or "significant."
He has significant resources and is able to buy the house.
He has considerable resources and is able to buy the house.
In antonym requests, context is often essential. It would be fairer if the same context were kept for 'negligible' and for the requested opposite. For example, "air resistance is negligible while porridge resistance is ??". And for this particular context, the already proposed 'significant' fits (as well as others, such as 'critical'; okay, I'm stretching it a bit).
Introducing the bike perspective flattens the meaning of 'negligible' in that it makes one think along an axis in terms of distance. That is where measures and infinity jump in, with their own contextual problems. A related post about 'infinitesimal' documents the quandary ('finite' vs. 'infinite' vs. 'infinitesimal', also mentioned by Hunter Hogan here).
What is the opposite of 'blue'? This and like questions may be bent to make some sense, a different sense, or a very particular sense, by a context. In view of the RGB model, for example, the opposite of 'blue' is arguably 'yellow'.
Incommensurable : (TFD)
impossible to measure or compare.
incapable of being judged, measured, or considered comparatively.
- Any quantity, commensurable or incommensurable, can be expressed uniquely as a simple continued fraction, terminating in the case of a commensurable quantity, non-terminating in the case of an incommensurable quantity.
How about ad infinitum? From Merriam-Webster:
Ad infinitum (adverb or adjective)
without an end or limit
If someone were trying to ride a bike to the other side of the world, he or she would be riding a bike ad infinitum.
negligible - small enough to essentially be zero
inestimable - so large as to be unmeasurable