definitely

def·i·nite·ly | \ ˈde-fə-nit-lē

, ˈdef-nət- \

Definition of definitely

1 : in a definite way : in a way free of all ambiguity, uncertainty, or obscurity I will definitely be there. He's very smart and very funny and is definitely a practical actor. He comes to work to get his job done and to make the best movie possible …— Anna Kendrick Omaha is definitely not hip; green-haired XML programmers do not glide past gourmet coffee emporiums on Razor scooters.— Adam Rogers

2a —used in speech as a forceful way of expressing agreement or saying "yes""Do you think they'll win?" "Definitely!"

b —used in speech in the phrase definitely not as a forceful way of expressing disagreement or saying "no""Do you agree with him?" "Definitely not!"