Rogets II: The New Thesaurus, Third Edition. 1995.
thorn
NOUN:
1. A sharp, pointed object: needle, prick, prickle, spine. SeeSHARP. 2. One that makes another totally miserable by causing sharp pain and irritation: trial. Informal :pain. Idioms: pain in the neck, thorn in the flesh (or side) . SeePAIN.