Interjection is a part of speech header, whose use at Wiktionary in practice differs from its definition, in part because the application of the definition is not clear. Interjections get only the briefest of mention in grammars, because they are isolated syntactically from surrounding utterances. An interjection is defined as a form, typically brief (one syllable or word), which is used most often as an exclamation or part of an exclamation. It has three typical characteristics:
- expresses an emotional reaction, often with respect to an accompanying sentence;
- is syntactically isolated from other accompanying expressions; and
- may include a combination of sounds not otherwise found in the language.
Examples that most would include as interjections include:
Even these only imperfectly fit the defining criteria above. "Ow" and "ouch" include no sounds not elsewhere in English. "Ow" and "ouch" express pain, which is not normally considered an emotion. "Psst" is not associated with any emotion.
And any complete sentence is as syntactically isolated from another sentence as an interjection is from any surrounding sentence.
An important question for a dictionary is "Under what circumstances should a word be classified as an interjection? The answer is not all obvious as words of almost every part of speech can also be used in ways that share some of these characteristics. The phonological characteristic is not a good discriminator as it is only sometimes applicable.
Almost all parts of speech are sometimes used as interjections. The exception would seem to be prepostion. All of the following can be found to sometimes fit the first two criteria:
- Nouns: fucker!
- Verbs: Agreed! Begone! Damn!
- Proper nouns: Christ!
- Pronouns: My! Whatever!
- Adjectives: Nice! Tough!
- Adverbs: Now! Absolutely!
- Conjunction: Because!