Definition

Interjection is a part of speech that expresses various emotions without naming them.

Structure

Simple	Composite
Consists of one word	Consists of multiple words
ah, oh, eh, pooh, hum, fie, bravo, hush well, here, there, come,	heigh-ho! hey-ho! holla-ho! gee-ho! dear me, confound it, hang it

Meaning

According to their meaning interjections fall under two main groups,

#1. Emotional interjections express the feelings of the speaker. They are: ah, oh, eh, bravo, alas, etc.

…A man jumped on top of the barricade and waving exuberantly shouted, “Americans! Hurrah!” (Heym) (joy)

Alas! The white house was empty and there was a bill in the window “To let”.(Dickens) (sorrow)

Psha! There’s no possibility of being witty without a little, ill nature. (Sheridan) (contempt)

Oh, bother! I can’t see anyone now. Who is it? (Shaw) (indignation)

“Dear me!” says Mr. Chillip meekly smiling with something shining in his eyes. (Dickens) (surprise)

#2. Imperative interjections show the will of the speaker or his order or appeal to the hearer. They are: here, hush, sh-sh, well, come, now, etc.

Here! I’ve had enough of this. I’m going. (Shaw) (protest)

“Upon my word I was not awake, sir,” replied Oliver earnestly. “I was not, indeed, sir.” “Tush, tush, my dear!” said the Jew abruptly resuming his old manner. (Dickens) (order)

Origin

Interjections may be primary and secondary.

#1. Primary interjections are not derived from other parts of speech. Most of them are simple words: ah, oh, eh, pooh, hum, fie, bravo, hush.

Only a few primary interjections are composite: heigh-ho! hey-ho! holla-ho! gee-ho!

#2. Secondary interjections are derived from other parts of speech. They are homonymous with the words they are derived from.

They are: well, now, here, there, come, why, etc.

NOTE: Derivative interjections should not be confused with exclamation-words, such as nonsense, shame, good, etc.)

Derivative interjections may be simple: well, here, there, come, etc., and composite: dear me, confound it, hang it, etc.

Function

Interjections are used as independent sentence-words or independent elements of the sentence.

Daughter: Sixpence thrown away! Really mamma, you might have spared Freddy that.
Gentelman: Phew! (Shaw)

Well, I don’t like those mysterious little pleasure trips that he is so fond of taking. (Voynich)

NOTE: Formulas of courtesy, greetings, etc. should not be regarded as interjections. Thus, good-bye, thank you are not interjections because they do not express emotion or will.