“And you’re definitely definite about that; like, for definite?”

D-E-F-I-N-I-T-E-L-Y

Not definately.
Not definatly.
Not definently.
Not definantly.
Not definetly.

And you could try defiantly, but I wouldn’t recommend it.

There’s only one way to spell that word and it is is d-e-f-i-n-i-t-e-l-y.

Up with this I will not put!

Vizzini: “He didn’t fall? In-con-ceiv-able!”
Inigo: “You keep using that word. I do not think it means what you think it means.”