An interjection is a cry or other exclamatory sound expressing surprise, anger, pleasure or some other emotion or feeling.
Examples : O (or oh), ah, hullo (holloa, halloo), bah, pshaw, fie, whew, tut-tut, st (often spelled hist), ha, aha, ha ha, ho, hey, hum, hem, heigh-ho (heigh-o), alas, bravo, lo.
When written, interjections are often followed by an exclamation point (!).
Among interjections are properly included calls to animals (like “whoa!") and imitations of sounds such as “mew!" “cock-a-doodle-do!" “ding dong!" “swish!" “tu-whit-tu-who!"
Interjections usually have no grammatical connection with the phrases or sentences in which they stand.
Hence they are counted among the independent elements of a sentence.
Sometimes, however, a substantive is connected with an interjection by means of a preposition. Thus….
1. for a camera!
2. Alas for my hopes!
Adjectives and adverbs are also found in this use such as….Good for you!" “Up with it!"
Note : All such expressions are often regarded as elliptical sentences, as if “O for a camera!" stood for “O, I wish for a camera!" and “Good for you!" for “That is good for you!" But it is better to treat them as exclamatory phrases. Other exclamatory phrases are “Dear me!" “Goodness gracious!" “O my!" and the like.
Almost any part of speech may be used as an exclamation.
1. Nonsense! I do not believe it.
4. Good! I like that!
8. Back, villains!
9. I! not a bit of it!
Such words are often called interjections, but it is better to describe them as nouns, adjectives, etc., used in exclamation and to confine the term interjection to words which belong to no other part of speech.
Note : Thus nonsense! and fire! are nouns in the exclamatory nominative; I! is a pronoun in the same construction; halt! is a verb in the imperative (compare hark! hush! behold! look!); good! is an adjective; forward! on! away! and back! are adverbs; but! is a conjunction.
The following examples illustrate various exclamatory expressions…..words, phrases and sentences.
1. How late I shuddered on the brink! - Young.
2. “Right! right!" a thousand tongues exclaimed. - Southey.
3. The pale stars are gone! - Shelley.
4. Poor widowed wretch! ’twas there she wept in vain. - Campbell.
5. O heartfelt raptures! Bliss beyond compare! - Burns.