Always Open, Nonstop
If rest is nothing then there are no holidays. If there are no holidays, then that means a place is always open, nonstop.
This is a jukugo word, which usually means on'yomi readings from the kanji. If you know the readings of your kanji you'll know how to read this as well.
Koichi usually works without taking holidays.
Kana and Mami are making WaniKani example sentences without any breaks.
Tofugu’s website is always open, twenty-four hours a day, every day of the year.