What are the antonyms for "fixture"?

Antonyms for "fixture" vary by context because the word has multiple senses. In the architectural and real estate sense, where a fixture is an item permanently attached to property, the opposites include "chattel" and "personal property" (legal terms for movable possessions), "movable," "free-standing item," "loose item," "furnishing," and "fitting" (in British usage, where fittings are removable items like curtains and plug-in appliances, in contrast to fixed fixtures). A mirror bolted to the wall is a fixture; a mirror leaning on the wall is its opposite, a movable chattel. When "fixture" describes a person or thing permanently established in a place, the antonyms include "transient," "newcomer," "outsider," "occasional visitor," "passerby," "temporary presence," and "impermanent feature"; the opposite of a fixture at a club would be someone who rarely visits or has just arrived. When "fixture" refers to a scheduled sporting match, the opposites include "cancellation," "postponement," "unofficial game," or "unscheduled event," since a fixture is by definition fixed on a calendar. In the general sense of fixed positioning, antonyms include "mobile object," "portable item," "detachable part," "removable piece," and "loose component." In engineering, where a fixture holds a workpiece rigidly, the conceptual opposite is an unclamped, freely moving workpiece or a flexible setup. Because "fixture" has no single universal opposite, the appropriate antonym must be chosen based on whether the intended meaning is physical attachment, social permanence, or scheduled arrangement.