Definitely not!

definitely not

Absolutely not! A: "Now, be honest—have you ever stolen money from this company?" B: "No, definitely not!"
See also: definitely, not

Definitely not!

 and Certainly not!
No, without any doubt at all. (Compare this with Absolutely not!) Bill: Will you lend me some money? Bob: No way! Definitely not! Bob: Have you ever stolen anything? Fred: Certainly not!
See also: Definitely