Solid
Firm, Stout, Sturdy
noun, な adjective
A stubborn height is a shorter, stockier height. It makes a person especially solid, firm, and stout.
This is a jukugo word that uses the on'yomi readings of the kanji. You should be able to read this on your own.
土台はできるだけ頑丈にしておいた方がいいですよ。
You should make the foundation as firm as possible.
この車はとても頑丈にできています。
This car is solidly built.
眼鏡屋さんで、とても頑丈な眼鏡を作ってもらいました。
I had a really solid pair of glasses made by my optician.