Synonyms for Immobile (same or very similar meaning)
WordNet sense 1 (not moving or operating freely):
stiffWordNet sense 2 (not able or intended to be moved):
immovable, unmovableWordNet sense 3 (securely fixed in place):
fast, firmWordNet sense 4 (securely placed or fastened or set):
fixedFrom the ODE community, based on WordNetadd/edit