RUCKSACK is a playable word

rucksack Scrabble® Dictionary

noun
pl. rucksacks
a knapsack
50 Playable Words can be made from "RUCKSACK"
   2-Letter Words (4 found)
   3-Letter Words (15 found)
   5-Letter Words (8 found)
   6-Letter Words (2 found)
   8-Letter Words (1 found)