no-pants day Share definition Flag 1) a day to stay in doors and relax in one's pajamas. 2) 24-hour period with no responsibility. We stayed at home and watched movies all day...it was a wonderful no-pants day. no-pants day by Cycleman January 4, 2014 0 0 Get merch Get the no-pants day mug. Buy Now — $32.95 See more merch