What is the antonym for "default" (computer science). For example there is "default value", how to say "not default"? Is there a one word for "not default" :)?

  • 2
    Maybe specific, customized, or user-defined. Apr 24, 2014 at 12:29
  • Ah, you mentioned it! I read it after writing an answer. Good to note that defined works alone as well.
    – Maulik V
    Apr 24, 2014 at 13:05
  • 1
    You're asking about something technical, but you haven't given enough information to get a meaningful answer, I'm afraid.
    – user230
    Apr 24, 2014 at 15:11
  • Like "specific", you could say "specified" values.
    – user3169
    Apr 25, 2014 at 2:19
  • 1
    If by "default value", you mean the value of a variable, be careful with saying "undefined value". The term "undefined value" can mean (and usually means) something different from an "unassigned value" or an "unset value". Apr 25, 2014 at 5:41

5 Answers 5


I know a bit of programming. And, it's surprising (I confirmed it with a profound programmer) that an opposite word to default value (strictly in computer science) is


Some programming languages take default values unless you define them. The moment you define them, they are overwritten.

So, I think in your context, not default is defined.

Other good alternatives, as said by Damkerng are customized, user-defined, specific.

  • 4
    default values are defined (system-defined not user-defined). Undefined values occur when defaults do not exist, and a needed value is not supplied.
    – Kaz
    Apr 24, 2014 at 23:29
  • @Kaz true but when we call default value it means the value is already there but since we haven't defined them, we won't call it as a defined value. Or in that sense, we'll have to redefine the value, which is not a preferred word in this case.
    – Maulik V
    Apr 25, 2014 at 5:13

This word has no clear semantic antonym.

It has a grammatical antonym, of course, which is simply the word non-default: the non prefix is used, usually with a hyphen. undefault is strange as an adjective, and indefault or adefault completely so. The un prefix can be used to negate the participial adjective defaulted, which is derived from the verb to default. If a financial loan is in good standing (payments are being made) we might say that it's an undefaulted loan. The question is, what does non-default mean: see the bottom of the answer.

A given parameter in a system can be either undefined, system-defined (default) or user-defined. Sometimes there is no system-defined state: a value for the parameter must be supplied, or else it is undefined.

Initial values that occur by fluke, and are not documented, are not defaults. For instance, if the value 42 occurs in RAM location 500 when power is applied to a device, isn't a default, even if it appears to be reliable on every power up. There is no documented guarantee, and the value may be different in another device from a different production run where a different memory chip was used or whatever. Defaults are predictable, documented initial values which are defined by the system (operating system, programming language, application, ...).

In some systems, parameters can begin in an undefined state, and there is an initialization procedure which sets them to default values, which can be further configured ("overridden", "customized", "tweaked", ...).

In some systems, when values such as variables are defined, they never have an uninitialized state; if no initial value is supplied, there is an implicit one, and that constitutes a default.

Sometimes there are multiple levels of defaulting. A programming language might default global variables to zero. However, a program written in the language might define some variables with non-zero values. To the language, these values are non-default values, but to the user of the program, they are documented as that program's defaults.

It is not clear whether the initial, undefined state is the "opposite" of the default configuration, or whether the overridden states are the opposite, and this becomes even less clear if there are multiple levels of defaulting.

A user who only sticks with the default values will probably regard the uninitialized state as the opposite: the opposite of the configured (default) state. ("Order versus chaos.")

A user who doesn't think about the uninitialized state, but chooses between default and customized configurations might regard those two as opposites. ("My choice versus someone else's.")

The meaning of the non-default grammatical antonym of default tends to lean toward the latter definition. It would be strange to refer to a nonexistent or uninitialized value as non-default (even though, strictly speaking, that is true); non-default usually refers to a well-defined alternative to the default.

  • if it's not default you certainly have to define it. Default values are always created by the machines (though originally by humans!). I reconfirmed (after your comment/downvote) with five more programmers and since the OP is asking from their prospective, it's quite clear that if it's not default it's defined.
    – Maulik V
    Apr 25, 2014 at 15:23
  • ^ PERspective (viewpoint), not PROspective (expected future quality).
    – Kaz
    Apr 25, 2014 at 19:32
  • True. Thanks. That's what happens when I write with auto text on on my phone.
    – Maulik V
    Apr 29, 2014 at 6:26


Hit [Enter] to select the default value, or type your own custom value.

  • 1
    This should be the answer.
    – Pacerier
    Sep 19, 2017 at 21:24

You may use customized as the antonym of default.


From a programming perspective, I would say that a non-default value is either assigned or manually assigned.

  • If I were to build a user interface, I would say the contrary of default would be custom. This of course may work for you depending on the particular circumstance at hand. Nov 1, 2018 at 14:42

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