Healthful vs. Healthy (also Suspect vs. Suspicious and a host of other pairs)

healthful, adjective

1. Promoting or conducive to bodily health; health-giving, wholesome, salubrious.  b. Bestowing, promoting, or conducive to moral or spiritual welfare or prosperity; salutary, saving. (usage examples from 1398 through the C19)

2. Of persons, their actions, etc.: Full of or characterized by health; enjoying good health; healthy. Now rare. b. Marked by intellectual or moral soundness. (usage examples from 1550-1884)

healthy, adjective

1. Possessing or enjoying good health; hale or sound (in body), so as to be able to discharge all functions efficiently.    2. a. Conducive to or promoting health; wholesome, salubrious; salutary. Also fig. (usage examples from 1550-1879)

3. a. Denoting or characteristic of health or sound condition (lit. and fig.); opp. to morbid. [3.] c. spec. Of appetite or other propensity: of a size considered indicative of good health (freq. with implication of largeness). Hence (colloq.) more generally, ample, considerable; substantial, sizeable.  (usage examples from 1836-1990)