Editing Opposite (section)

==General discussion==
Opposition is a semantic relation in which one word has a sense or meaning that negates or, in terms of a [[Level of measurement|scale]], is distant from a related word. Some words lack a lexical opposite due to an [[accidental gap]] in the language's [[lexicon]]. For instance, while the word "devout" has no direct opposite, it is easy to conceptualize a scale of devoutness, where "devout" lies at the positive end with a missing counterpart at the negative end. In certain cases, opposites can be formed with prefixes like "un-" or "non-," with varying levels of naturalness. For example, "undevout" is found in Webster's 1828 dictionary, while the prefix pattern of "non-person" could theoretically extend to "non-platypus."

Conversely, some words appear to be derived from a prefix suggesting opposition, yet the root term does not exist. An example is "inept," which seems to be "in-" + *"ept," although the word "ept" itself does not exist{{Citation needed|date=July 2024|reason=inept = non apt; better example needed}}. Such words are known as [[unpaired word|unpaired words]].
Opposites may be viewed as a special type of incompatibility.<ref>Incompatibility can be compared to [[exclusive disjunction]] in logic.</ref> Words that are incompatible create the following type of [[entailment]] (where ''X'' is a given word and ''Y'' is a different word incompatible with word X):<ref>There are four types of entailment useful to lexical semantics:
* ''unilateral entailment'': ''It's a fish'' unilaterally entails ''It's an animal''. (It is unilateral, i.e. one-directional, because ''It's an animal'' does not entail ''It's a fish'' since ''it'' could be a dog or a cat or some other animal.)
* ''[[logical equivalence]]'' (or ''multilateral entailment''): ''The party commenced at midnight'' entails ''The party began at midnight'' and ''The party began at midnight'' also entails ''The party commenced'' since both cannot be simultaneously true. On the Aristotelian square of opposition, the A and E type propositions (''All As are Bs'' and ''No As are Bs'', respectively) are contraries of each other. Propositions that cannot be simultaneously false (e.g. 'Something is red' and 'Something is not red') are said to be '''subcontraries'''.
* ''contradiction'': ''It's dead'' entails ''It's not alive'' and ''It's not alive'' entails ''It's dead'' and ''It's alive'' entails ''It's not dead'' and ''It's not dead'' entails ''It's alive''. ''It's dead'' and ''It's alive'' are said to be in a contradictory relation.</ref>

: sentence ''A is <u>&nbsp;X&nbsp;</u>'' &nbsp;entails&nbsp; sentence ''A is not <u>&nbsp;Y&nbsp;</u>'' <ref>Stated differently, if the proposition expressed by the sentence ''A is <u>&nbsp;X&nbsp;</u>'' is true, then the proposition expressed by the sentence ''A is not <u>&nbsp;Y&nbsp;</u>'' is also true.</ref>

An example of an incompatible pair of words is ''cat : dog'':

: ''It's <u>a cat</u>'' &nbsp;entails&nbsp; ''It's not <u>a dog</u>'' <ref>It is assumed here that ''it'' has the same [[referent]].</ref>

This incompatibility is also found in the opposite pairs ''fast : slow'' and ''stationary : moving'', as can be seen below:

''It's <u>fast</u>'' &nbsp;entails&nbsp; ''It's not <u>slow</u>'' <ref>It is also assumed here the reference point of comparison for these adjectives remains the same in both sentences. For example, a rabbit might be fast compared to turtle but slow compared to a sport car. It is essential when determining the relationships between the lexical meaning of words to keep the situational context identical.</ref>

:''It's <u>stationary</u>'' &nbsp;entails&nbsp; ''It's not <u>moving</u>''

Cruse (2004) identifies some basic characteristics of opposites:

* ''binarity'', the occurrence of opposites as a lexical pair
* ''inherentness'', whether the relationship may be presumed implicitly
* ''patency'', the quality of how obvious a pair is

Some [[Planned language|planned languages]] abundantly use such devices to reduce vocabulary multiplication. [[Esperanto vocabulary#Affixes|Esperanto]] has ''mal-'' (compare ''bona'' = "good" and ''malbona'' = "bad"), [[Damin]] has ''kuri-'' (''tjitjuu'' "small", ''kuritjitjuu'' "large") and [[Newspeak]] has ''un-'' (as in ''ungood'', "bad").

Some classes of opposites include:

* ''antipodals'', pairs of words which describe opposite ends of some axis, either literal (such as "left" and "right", "up" and "down", "east" and "west") or figurative or abstract (such as "first" and "last", "beginning" and "end", "entry" and "exit")
* ''disjoint opposites'' (or "incompatibles"),  members of a set which are mutually exclusive but which leave a ''lexical gap'' unfilled, such as "red" and "blue", "one" and "ten", or "Monday" and "Friday".
* ''reversives'', pairs of verbs which denote opposing processes, in which one is the reverse of the other. They are (or may be) performed by the same or similar subject(s) without requiring an object of the verbs, such as "rise" and "fall", "accelerate" and "decelerate", or "shrink" and "grow".
* [[Converse (semantics)|''converses'']] (or ''relational opposites'' or ''relational antonyms''), pairs in which one describes a relationship between two objects and the other describes the same relationship when the two objects are reversed, such as ''parent'' and ''child'', ''teacher'' and ''student'', or ''buy'' and ''sell''.
* ''overlapping antonyms'', a pair of comparatives in which one, but not the other, implies the positive:
** An example is "better" and "worse". The sentence "''x'' is better than ''y''" does not imply that ''x'' is good, but "''x'' is worse than ''y''" implies that ''x'' is bad. Other examples are "faster" and "slower" ("fast" is implied but not "slow") and "dirtier" and "cleaner" ("dirty" is implied but not "clean"). The relationship between overlapping antonyms is often not inherent, but arises from the way they are interpreted most generally in a language. There is no inherent reason that an item be presumed to be bad when it is compared to another as being worse (it could be "less good"), but English speakers have combined the meaning semantically to it over the development of the language.