Etymology From Late Latin explētīvus (“serving to fill out”), from Latin explētus, the perfect passive participle of expleō (“fill out”), itself from ex (“out, completely”) + *pleō (“fill”).
1
Serving to fill up, merely for effect, otherwise redundant.
No one entered more fully than Shakespeare into the character of this species of poetry, which admits of no expletive imagery, no merely ornamental line.1839, Henry Hallam, Introduction to the Literature of Europe, volume 3, London: John Murray, →OCLC, page 501:
deprecating being taken for ſerious, or to be underſtood that he meaneth any thing by them; but only that he uſeth them as expletive phraſes ... to plump his ſpeech, and fill up ſentences.1683, Isaac Barrow, The Works of the Learned Isaac Barrow, London: M. Flesher for B. Aylmer, →OCLC, Against vain and raſh Swearing:
Etymology From Late Latin explētīvus (“serving to fill out”), from Latin explētus, the perfect passive participle of expleō (“fill out”), itself from ex (“out, completely”) + *pleō (“fill”).
1
A profane, vulgar term, notably a curse or obscene oath.
If we don't take advantage of any [expletive] in any way, then it's our loss.
2
Human sciences, Linguistics, Sciences A word without meaning added to fill a syntactic position.
3
Human sciences, Linguistics, Sciences A word that adds to the strength of a phrase without affecting its meaning (such as fuckin in "there's no fuckin way he's gonna get away with it").
4
An obscene or otherwise offensive interjection (such as shit, fuck, or damn it).