In pragmatics (linguistics), deixis is a process whereby words or expressions rely absolutely on context. The origo is the context from which the reference is made, in other words, the viewpoint that must be to be understood in order to interpret the utterance. (If Tom is speaking and he says "I", he refers to himself, but if he is hearing Betty and she says "I", then the origo is with Betty and the reference is to her.) A word that depends on deictic clues is called a deictic or a deictic word. Deixis is a type of exophora.

Pro-forms are generally considered to be deictics, but a finer distinction is often made between personal pro-forms such as I, you, and it (commonly referred to as personal pronouns) and pro-forms that refer to places and times such as now, then, here, there. In most texts, the word deictic implies the latter but not necessarily the former. (In philosophical logic, the former and latter are collectively called indexicals.)

It is common for languages to show at least a two-way referential distinction in their deictic system: proximal, i.e. near or closer to the speaker, and distal, i.e. far from the speaker and/or closer to the addressee. English exemplifies this with such pairs as this and that, here and there, etc. In other languages the distinction is three-way: proximal, i.e. near the speaker, medial, i.e. near the addressee, and distal, i.e. far from both. This is the case in Romances and Japanese.

Spatial deictics are often reused as anaphoric pro-forms that stand for phrases or propositions (that is, items of discourse, not items of the outside reality). Consider the following statement:

There may be ice hidden in unexplored places of the Moon. This ice could be useful for future lunar expeditions.

In the above example, this ice is not near the speaker in the physical sense, but the deictic doesn't refer to real ice. This ice refers to the phrase ice hidden in unexplored places, which is conceptually near the speaker in the discourse flow.

Types of deixis

• Person deixis: see grammatical person.
• Discourse deixis : where reference is being made to the current discourse or part thereof. Examples: "see section 8.4", "that was a really mean thing to say", "This sentence is false ". The later is an example of token-reflexive discourse deixis, in which a word in the utterance refers to the utterance itself.
• Switch reference is a type of discourse deixis, and a grammatical feature found in some languages, which indicates whether the argument of one clause is the same as the argument of the previous clause. In some languages this is done through same subject markers and different subject markers. In the traslated example "John punched Tom, and left-[same subject marker]," it is John who left, and in "John punched Tom, and left-[different subject marker]," it is Tom who left.
• Emphatetic deixis : where different forms of the deictic are used to indicate the speakers emotional closeness or distance from the referent.
• Place deixis : a spatial location relative to the spatial location of the speaker. it can be proximal or distal, or sometimes medial. It can also be either bounded (indicating a spatial region with a clearly defined boundary, e.g. in the box) or unbounded (indicating a spatial region without a clearly defined boundary, e.g. over there)
• Social deixis : is the use of different deictics to express social distinctions. an example is difference between formal and polite pro-forms. Relational social deixis is where the form of word used indicates the relative social status of the addressor and the addressee. For example, one pro-form might be used to address those of higher social rank, another to address those of lesser social rank, another to address those of the same social rank. By contrast, absolute social deixis indicates a social standing irrespective of the social standing of the speaker. Thus, village chiefs might always be addressed by a special pro-form, regardless of whether it is someone below them, above them or at the same level of the social hierarchy who is doing the addressing.
• Time deixis : is reference made to particular times relative to some other time, most currently the time of utterance. For example the use of the words now or soon, or the use of tenses.