What does "expletive" mean?

Expletive: Filling up; hence, added merely for the purpose of filling up; superfluous. "Expletive imagery." Hallam. Expletive phrases to plump his speech. Barrow.

Additional senses

  1. 2.A word, letter, or syllable not necessary to the sense, but inserted to fill a vacancy; an oath. While explectives their feeble aid to join, And ten low words oft creep in one dull line. Pope.

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