Definition of "thorny"

the steep and thorny way to heaven

c. 1599–1602 (date written), William Shakespeare, “The Tragedie of Hamlet, Prince of Denmarke”, in Mr. William Shakespeares Comedies, Histories, & Tragedies […] (First Folio), London: […] Isaac Iaggard, and Ed[ward] Blount, published 1623, [Act I, scene iii]

Museums have recently begun to confront the same thorny question, with several issuing public apologies for collecting the remains of people believed or known to have been enslaved.

2021 October 10, Caroline Anders, “A TikTok bone salesman’s wall of spines reignites ethical debate over selling human remains”, in The Washington Post‎

Come, Jo, don't be thorny. After studying himself to a skeleton all the week, a fellow deserves petting, and ought to get it.

1868, Louisa May Alcott, Good Wives