Definition of decidedly adverb from the Oxford Advanced American Dictionary
decidedly
adverb
/dɪˈsaɪdədli/
1 (used with an adjective or adverb) definitely and in an obvious wayAmy was looking decidedly worried.Their relationship is beginning to look decidedly shaky.2in a way that shows that you are sure and determined about something“I won't go,” she said decidedly.