What is a good antonym for redundant?

The definition I am looking to find an antonym for is:

Source: Dictionary.com



  1. Engineering.
    d. (of a device, circuit, computer system, etc.) having excess or duplicate parts that can continue to perform in the event of malfunction of some of the parts.

Wikipedia has a page that uses this definition. Wikipedia defines this kind of redundancy as "duplication of critical components".

Used in a paragraph, "A software product can be installed redundantly or [non-redundantly]. The purpose of installing the product redundantly would be to allow for high availability. If one side goes down, then the other side immediately takes over. This is common practice in hardware and software industry."

I prefer a single word, but a phrase is also acceptable. I also prefer neutral or positive connotations. "Low availability" has negative connotations.

  • 2
    What is being negated, the duplication or the critical nature? Duplication of non-critical parts? Failure to duplicate critical parts?
    – TimR
    May 22, 2015 at 14:19
  • 1
    @MarvMills Nothing is being taken away or removed. I'm not looking for a verb. I'm looking for an adjective. I don't want to convey the message that it was or was not redundant in the past, or will or will not be in the future. I just want to describe the system as it is now: The system is not redundant.
    – Rainbolt
    May 22, 2015 at 15:21
  • 1
    @Rainbolt: Your question is not very clear: words have antonyms; phrases do not. You want the antonym of duplication of critical components' held together like that. Your question is borderline gibberish.
    – TimR
    May 22, 2015 at 19:40
  • 4
    @Rainbolt: This is not meaningful: A word or phrase that means the opposite of "duplication of critical components". A phrase with the opposite meaning is "no duplication of critical components". The opposite of "redundant" is "not redundant". It's like asking for the opposite of "in triplicate".
    – TimR
    May 22, 2015 at 19:52
  • 1
    I would say "critical".
    – Hot Licks
    May 22, 2015 at 19:56

10 Answers 10


Just negate the term with non- to form non-redundant (or nonredundant). As with redundant itself, an engineering context directs the reader or hearer to understand the term in the engineering sense.

Wiktionary gives primacy to the closed spelling; OED offers only the hyphenated one, with examples but no definition (since defining the negation of redundant would be redundant).

  • 1
    As an engineer with may years of experience, I would vouch for this answer. But it would be better to include some examples in your answer. A simple Google search on phrases like "non-redundant design", "non-redundant electrical design", "non-redundant mechanical design", and "non-redundant systems", would provide many examples of its use. Comments don't provide enough room to link to them. (I understand this might be a circular argument, but, apart from my own experience, it does show that the term is widely used.) May 23, 2015 at 3:14

That missile is a single point of failure device, which is why it's not man rated.

  • This is the answer (IMO).
    – Drew
    May 22, 2015 at 14:51
  • "Single point of failure" has a negative connotation, though. "Non-redundant" systems are sometimes much better options when cost is a more important factor than availability. So even though they are are a "single point of failure" the resulting failure is minor or negligible. That being said, I don't have a better answer.
    – mfoy_
    May 22, 2015 at 15:34
  • So... what is the antonym of "redundant"? I don't think you provided that. You have only given an attribute that a non-redundant device might have. (And even some redundant devices still suffer from single points of failure.) May 23, 2015 at 0:07


For example

Oracle ASM is a volume manager and a file system for Oracle database files that supports single-instance Oracle Database and Oracle Real Application Clusters (Oracle RAC) configurations.
Oracle Grid Infrastructure for a Standalone Server

In your case

A software product can be installed redundantly or as a single-instance. The purpose of installing the product redundantly would be to allow for high availability. If one side goes down, then the other side immediately takes over. This is common practice in hardware and software industry.


I think that depending on the context, you may want to avoid bothering with an antonym of "redundantly" altogether. Consider your example phrase: "A software product can be installed redundantly or non-redundantly".

You need the adjective "redundantly" to modify "installed" because by default things are not installed redundantly. So your phrase naturally sounds quite clunky.

Instead, consider the following phrasings:

  • "A software product can be installed, with optional redundancy"

  • "A software product can be installed alone or installed with redundancy"

  • "A software product may be installed normally, or with redundancy"

  • 1
    I'd say "A software product can be installed with or without redundancy" over those options. Alternatively, if you're just trying to introduce the concept of redundancy and its purpose, just say "A software product can be installed redundantly" or "...with redundancy". Leave the alternative unstated, since I think the only way you could state it would be with "non-redundantly", which is exactly the word that would probably come to a reader's mind if they tried to fill in the blank.
    – Terry N
    May 23, 2015 at 2:34

Critical or Mission-critical conveys the importance of the component while retaining the same sort of technical context.

  • 4
    If something is mission-critical it better be installed redundantly. I think you've misunderstood what "installed redundantly" means. It means that it is installed with redundancy (ie. duplicated components, multiple instances, etc) so that if one breaks there are identical components available to take over automatically. For example, redundant power supplies, or load-balanced servers.
    – mfoy_
    May 22, 2015 at 15:38
  • @mfoy_, I think you've misunderstood how "mission critical" components are handed by normal people. :-) Yes, you should install redundant components and set up automatic failover, but lots of people go with the "buy something and assume it will never break" strategy even when they know it's a mission-critical component.
    – Hellion
    May 22, 2015 at 15:43
  • 1
    @Hellion but a component being "mission-critical" and "installed redundantly" are not directly related. One is not the opposite of the other; it is a whole other dimension.
    – mfoy_
    May 22, 2015 at 15:47
  • @Mfoy: You are talking as an engineer, Hellion is addressing how us normals talk ;-) I am in no doubt that most of us misuse "redundant" and think it means "not necessary". The usage of making you redundant = you're fired may contribute to this.
    – David Pugh
    May 22, 2015 at 16:30
  • Critical works quite well here, mission critical really doesn't.
    – Chris H
    May 22, 2015 at 20:04

You can use clustered for plural and non-clustered for the singular. That is a common term in IT when dealing with server infrastructure.



The term standalone is often used for this use case.

Self-contained and usually independently operating: a standalone computer terminal.
The Free Dictionary

For example, RedHat documents that:

A cluster does not directly manage either configuration properties or deployed content. However, if two EAP 6 standalone servers are in the JBoss ON inventory, then JBoss ON can work somewhat as a bridge, comparing the configuration and content deployments between servers and copying between them. That comparison is what the addToCluster function uses to add a standalone server to a cluster. It uses the configuration properties in an existing cluster member and copies them over to the standalone server.


Most of what I can think of to describe 'non-redundancy' is either a commentary on the effect of the lack of redundancy, or a word that means the same thing but lacks the same connotation.

A few ideas are:

  • Discrete
  • Standalone
  • Individual

And these could also be applied, depending on context:

  • Fragile
  • Choke-point
  • Unique
  • Unaided

And if you want to get tongue-in-cheek:

  • Dundant
  • Aredundant

Singly. You're only installing one of them, not several for fail-over.


Used in a paragraph, "A software product can be installed redundantly or [non-redundantly]. The purpose of installing the product redundantly would be to allow for high availability. If one side goes down, then the other side immediately takes over. This is common practice in hardware and software industry."

In mission-critical scenarios, best practice is to design for redundancy in order to eliminate single points of failure. If a component should fail, a redundant component can be brought online manually by the user—or automatically if the system is self-monitoring and self-correcting. In a simple "failover" strategy, the redundant component is kept on standby, whereas in a more complex system with real-time "load balancing" capabilities, an array of redundant components is put in place and the components share the load.

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