[2] Expletives are not insignificant or meaningless in all senses; they may be used to give emphasis or tone, to contribute to the meter in verse, or to indicate tense.
For example, in the sentence, "The bloody thing is shit, hey": The popularity of the phrase "expletive deleted" derives from the Watergate hearings in the United States in the 1970s, where the phrase was used to replace profanity that occurred in the transcripts of conversations that were recorded in the White House.
[14] At the start of the modern English era, the use of the word "do" as an expletive came into fashion with no fixed principle guiding it.
It is a term for a pronoun that is used at the start of a sentence or clause when the referent is not immediately known, but an argument for the verb is syntactically required.
In a clause like "it is raining" the referent of the pronoun "it" is not obvious, and is the subject of discussion and alternate theories among linguists.