invariable UK /ɪnˈvɛə.ɹi.ə.bl̩/US /ɪnˈvɛɹ.i.ə.bl̩/adjective 3noun 1forms 1 adjective3 •Not variable; unalterable; uniform; always having the same value.Physical laws which are invariable. — 1860 •Constant. •That cannot undergo inflection, conjugation or declension.The French adjective marron ‘brown’ is invariable: it does not take the usual s in the plural. noun1 •Something that does not vary; a constant. formsinvariables
