untucked
Untuck your shirt, lie back, and relax.
Someone had untucked the sheet at the foot end of the bed and folded it up.

SMART Vocabulary: related words and phrases

Unfastening and opening
break something open
breaker
decongestion
gape
let/set something looseidiom
loose
shut (someone) up
steam
tease
tease something out
the earth/ground/floor opensidiom
unbolted
unbuckle
unfold
unknot
unlace
unlock
unlockable
unpick
unzip