thorny

adjective, thorn·i·er, thorn·i·est.

1. abounding in or characterized by thorns; spiny; prickly.
2. thornlike.
3. overgrown with thorns or brambles.
4. painful; vexatious: a thorny predicament.
5. full of difficulties, complexities, or controversial points: a thorny question.

adjective thornier or thorniest

1. bearing or covered with thorns
2. difficult or unpleasanta thorny problem
3. sharp

adj.Old English þornig; see thorn + -y (2). Figurative sense is attested from mid-14c. Related: Thorniness.