Definition of "unwholesome"

Caliban: As wicked dewe, as ere my mother bruſh'd / With Rauens feather from vnwholeſome Fen / Drop on you both : A Southweſt blow on yee, / And bliſter you all ore.

1610–1611 (date written), William Shakespeare, “The Tempest”, in Mr. William Shakespeares Comedies, Histories, & Tragedies […] (First Folio), London: […] Isaac Iaggard, and Ed[ward] Blount, published 1623, [Act I, scene ii], page 4

Alas! he mastered not his destiny: I have said before, his ashes are in yonder urn. A few unwholesome dews on a summer night were mightier than all his science.

1832, Letitia Elizabeth Landon, Heath's Book of Beauty, 1833, The Enchantress, page 17

There was something indefinably unwholesome about him. Something lean and snakelike.

2022, Ian McEwan, Lessons, page 184