My explanation is also right on Su.Ki. is exactly correct to define this words for you, and definitely not wrong one for sure.

I agree with Su.Ki. "I will definitely be at the party tomorrow" There is no doubt you will be at the party. Exactly and precisely are used to emphasise accuracy. "There is exactly 10 millilitres of liquid in the test tube" I hope that helps!

'Exactly' means 'precisely'. It is exactly 8 o'clock. You must do exactly what I say. 'Definitely' means that you are sure about something. There is no doubt. I know that definitely didn't leave my phone at home. I clearly remember picking it up and taking it out with me.