HILLING is a playable word

hill Scrabble® Dictionary

verb
hilled, hilling, hills
to form into a hill (a rounded elevation)
18 Playable Words can be made from "HILLING"
   2-Letter Words (4 found)
   3-Letter Words (6 found)
   4-Letter Words (6 found)
   5-Letter Words (1 found)
   7-Letter Words (1 found)