形容詞 thorny:

1. bristling with perplexities
2. having or covered with protective barbs or quills or spines or thorns or setae etc.
   同義詞：barbed, barbellate, briary, briery, bristled, bristly, burred, burry, prickly, setose, setaceous, spiny

1. It's a thorny subject.
   這是個棘手的問題。
2. Cacti are thorny.
   仙人掌多刺。