Healthy, sound, wholesome, robust, hale, well are comparable when meaning having or manifesting health of mind or body or indicative of such health.
Healthy may imply the possession of full vigor and strength of body or mind or it may merely imply freedom from signs of disease or abnormality. Often the term applies not to one having health but to what manifests one’s health or vigor or serves as a sign of it.
Sound even more strongly implies the possession of perfect health or the absence of all defects and therefore suggests not even the slightest sign of disease or of physical weakness or defect.
Wholesome (see also HEALTHFUL ) implies a healthiness that impresses others favorably, especially as indicative of a person’s physical, mental, and moral soundness or often more specifically of a person’s balance or equilibrium.
Robust implies the antithesis of all that is delicate; it usually connotes manifest vigor of health as shown in muscularity, fresh color, a strong voice, and an ability to work long and hard.
Hale, which is a close synonym of sound, is applied chiefly to elderly or aged persons who not only show no signs of infirmity or senility but manifest qualities of men in their prime.
Well, which is commoner as a predicative than as an attributive adjective, is a rather noncommittal term; it implies freedom from disease or illness but does not necessarily suggest soundness or robustness.