From Longman Dictionary of Contemporary Englishthornythorn‧y /ˈθɔːni $ ˈθɔːrni/ adjective 1 → a thorny question/problem/issue etc2 HBPa thorny bush, plant etc has thorns —thorniness noun [uncountable]
Examples from the Corpus
thorny• He may touch on several thorny border issues, such as immigration, sewage management and economic development.• Scritch, scratch, scramble, through the thorny bushes!• It is here that some of the thorniest decisions arise about choice and independence.• The ongoing success of his department validated his approach to the thorny problem of appraising individual effectiveness.• None of these struck me as particularly penetrating answers to a thorny problem.• The three still have to sort out the thorny question of who will run the centre and where it will be.• Before me lay a deep gulley choked with oleanders and thorny scrub, which descended precipitously down to the private beach. 