unsponˈtaneous,a. (un-1 7.) 1791Cowper Odyssey xx. 419 Wide they stretch'd Their jaws with unspontaneous laughter loud.1885Wesleyan Method. Mag. Dec. 955/2 Cases of unspontaneous Scripture⁓study.1896Westm.Gaz. 15 Dec. 2/1 His acting..is so mechanical,..so painfully unspontaneous.