Other forms: unscrewed, unscrewing, unscrews
To unscrew is to open or loosen something by twisting it. Anticlockwise, almost always.
The rule is lefty-loosey, and it holds for nearly every thread you will meet, with a handful of deliberate exceptions such as gas fittings and the left pedal of a bicycle, which are reversed on purpose so they do not undo themselves. It splits round an object. It covers lids, bolts and bulbs alike. The opposite is screw in, and a stuck lid is what rubber gloves are really for.
1verbunscrewTo loosen or remove something by turning it.
“You will need a cloth to unscrew that lid.”
Also accepted in games: twist off
Middle English
scrue
English
screw
English, today
unscrew
Built from
From un- + screw. screw comes from Middle English scrue. From Middle English screw, scrue (“screw”); apparently, despite the difference in meaning, from Old French escroue (“nut, cylindrical socket, screwhole”), from Latin scrōfa (“female pig”) through comparison with the corkscrew shape of a pig's penis. There is also the Old French escruve (“screw”), from Old Dutch scrūva "screw"; whence Middle Dutch schruyve (“screw”), which probably influenced or conflated with the aforementioned, resulting in the Middle English word. 2
Etymology from Wiktionary, CC BY-SA