na-adjective
constitutional; inherent; by nature
Describes a trait or tendency that is deeply rooted in a person's physical constitution, personality, or the fundamental nature of something. Often used in medical, psychological, or analytical contexts.
彼は体質的に太りやすい。
He is constitutionally prone to gaining weight.
その問題は
That problem is inherent, so it won't be fixed easily.
本質的 means 'essential' or 'fundamental', focusing on the core nature of something abstract, while 体質的 often relates to physical or organizational constitution.
Derived from 体質 (constitution, physical makeup) + 的 (adjectival suffix).