Synonyms for Immovable (same or very similar meaning)
WordNet sense 1 (property consisting of houses and land):
realty, real property, real estateWordNet sense 2 (not able or intended to be moved):
unmovable, immoveable, stabile, stabileWordNet sense 3 (not capable of movement or of being moved):
immobileFrom the ODE community, based on WordNetadd/edit