The word "un-screws" indicates the act of undoing a screw or unfastening a fastener. Therefore, possible antonyms for this term could be "screws in," "tightens," "fastens," "secures," or "fixes." Each of these antonyms represents the opposite action to that of unscrewing or undoing a screw. In some cases, the antonym might depend on the context, such as when discussing a loose screw that needs to be tightened or a new object that requires secure fastening. However, overall, the antonyms for "un-screws" involve actions that involve fixing or securing something firmly in place rather than undoing it.