pillis Share definition Flag (noun)a stray piece of lint or fuzz that can accumulate on sweaters, blankets, socks, or sweatshirts. plural form pilli "Hey Callie, you have a pillis on your sweater." pillis by Maggie P. January 31, 2008 0 0 Get merch Get the pillis mug. Buy Now — $32.95 See more merch