This is the 5469th most frequent Japanese word.
いなめ
The word "いなめ" does not exist as a standalone term in standard Japanese. Perhaps you meant "否めない (いなめない)," which means "cannot be denied" or "undeniable."
In this sentence, 'いなめ' is used in its negative inflection, combined with 'ない' to convey the meaning of 'undeniable' or 'cannot deny' regarding the fact.
彼が今回のプロジェクトを成功させたのは、いなめない事実だ。
It is an undeniable fact that he succeeded in this project.
The use of 'いなめ', here colloquially taking form as '否めない', emphasizes the action of negation regarding denying a certain observation.
このデザインに、独創性があることは否めない。
The originality present in this design cannot be denied.
In this complex sentence, 'いなめ' or its verb root within '否める' serves to question the applicability of the concept of negation in a conditional context.