unprompted
From Longman Dictionary of Contemporary Englishunpromptedun‧prompt‧ed /ʌnˈprɒmptɪd $ ʌnˈprɑːmp-/ adjective formal WILLINGsaid or done without anyone asking you to Quite unprompted, he offered to help.Examples from the Corpusunprompted• All four heads took the unprompted view that there was a desperate need for professional library staff in secondary schools.