Robust; physically fit and resistant to illness, or sturdy and strong in constitution or structure.
祖父は年齢の割に頑健で、畑仕事を毎日続けている。
My grandfather is remarkably robust for his age and continues working in the fields every day.
この橋は頑健な設計で、地震にも耐えられると言われている。
This bridge is robustly designed and is said to withstand earthquakes.
彼女は幼いころから頑健な体つきだった。
She has had a strong physique since childhood.