Origin: Latin suffix -ive
Expletive has 4 different meanings across 1 category:
a word or phrase conveying no independent meaning but added to fill out a sentence or metrical line
A profane, vulgar term, notably a curse or obscene oath.
Serving to fill up, merely for effect, otherwise redundant.
The word comes from Late Latin explētīvus, meaning "serving to fill out." It is derived from the Latin verb expleō, which combines ex ("out") and pleō ("to fill").