"Hardest" Natural Recordings by Native Speakers
The word "hardest" is a superlative form of the adjective "hard". It means the most difficult, challenging, or demanding. For example:
This math problem is the hardest one on the exam.
The hardest part of the hike was the steep incline.
She found it hardest to overcome her fear of public speaking.
A hardener is a substance or agent that hardens or strengthens something, such as a material or a bond. For example, a hardener might be added to a liquid mixture to make it set and become rigid, or it might be used to bond two surfaces together more effectively. Common uses of hardeners include in construction materials, adhesives, and encapsulations.