Correct spelling

indisputable

Correct spelling, explanation: indisputable is a pretty complex word consisting of a prefix in-, the base word dispute, and then the suffix -able. Technically, without any changes, the word would look like in-dispute-able, but in the case of the ea cluster, the spelling is generally adjusted to leave only a, hence indisputable is the correct spelling.

Definition of indisputable:
adjective
1. unquestionable, not to be discussed
Usain Bolt is an indisputable icon among sprinters.
The evidence was indisputable and the attacker was found guilty.


Incorrect spelling

indisputible

Incorrect spelling, explanation: indisputable is constructed by using the suffix -able, which does, in fact, have the variant -ible in some cases. It’s used in the word possible, for example, because here poss is not an independent word, the same with edible. Indisputible is incorrect, however, because it’s a compound of suffixes and the base word dispute which functions independently.