expletive

Short definition from Wiktionary

Adjective

1. 1
   Serving to fill up, merely for effect, otherwise redundant.
2. 2
   Marked by expletives (phrase-fillers).

Noun

1. 1
   A profane, vulgar term, notably a curse or obscene oath.
2. 2
   A word without meaning added to fill a syntactic position.
3. 3
   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. 4
   An obscene or otherwise offensive interjection (such as shit, fuck, or damn it).