na-adjective, noun which may take the genitive case particle 'no'
Describes something with substantial thickness, especially meat, flesh, or material that feels plump and substantial.
このステーキは肉厚でジューシーだ。
This steak is thick and juicy.
肉厚の葉
It's a plant characterized by its thick, fleshy leaves.
Compound of 肉 (niku, 'meat, flesh') and 厚 (atsu, 'thick'). The reading にくあつ is a straightforward combination of the on'yomi of each kanji.