the.com/expletive

means A word, often a swear word, inserted to express emotion or fill a grammatical slot rather than to add real meaning — the verbal equivalent of a placeholder brick.

from From Latin 'explere,' meaning 'to fill out' or 'to fill up' (ex- 'out' + plere 'to fill'). It first entered English as a grammatical term for a word that fills space in a sentence without adding content — think 'it' in 'it is raining.' The leap to 'swear word' is more recent, cemented in public memory when 1970s transcripts of White House tapes famously redacted profanity with the bracketed note '[expletive deleted]' — turning a dry linguistic term into the world's politest euphemism for a curse.