The definition of an expletive is a crude or obscene expression, or an unnecessary word or phrase used to fill space in a sentence for grammar or rhythm purposes.
(noun)See expletive in Webster's New World College Dictionary
noun
Origin: LL expletivus, serving to fill < L expletus, pp. of explere, to fill < ex-, out, up + plere, to fill: see full
adjective
See expletive in American Heritage Dictionary 4
noun
Origin:
Origin: From Late Latin explētīvus, serving to fill out
Origin: , from Latin explētus
Origin: , past participle of explēre, to fill out
Origin: : ex-, ex-
Origin: + plēre, to fill; see pelə-1 in Indo-European roots
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