definitive

1 ENTRIES FOUND:
definitive /dɪˈfɪnətɪv/ adjective
definitive
/dɪˈfɪnətɪv/
adjective
Britannica Dictionary definition of DEFINITIVE
[more definitive; most definitive]
1 
: not able to be argued about or changed : final and settled
2 
: complete, accurate, and considered to be the best of its kind

— definitively

adverb