[ex.ple.tive] n (1612) 1 a: a syllable, word, or phrase inserted to fill a vacancy (as in a sentence or a metrical line) without adding to the sense; esp: a word (as it in "make it clear which you prefer") that occupies the position of the subject or object of a verb in normal English word order and anticipates a subsequent word or phrase that supplies the needed meaningful content b: an exclamatory word or phrase; esp: one that is obscene or profane
2: one that serves to fill out or as a filling
[2]expletive adj [LL expletivus, fr. L expletus, pp. of explere to fill out, fr. ex- + plere to fill--more at full] (1666) 1: serving to fill up "~ phrases"
2: marked by the use of expletives