The term 'Be a Thorn in the Side of' can be expressed in three different ways using crossword solutions. The first solution is 'ANNOY' which is a five letter word meaning to cause someone to feel angry, frustrated, or irritated. The second solution is 'IRK' which is a three letter word meaning to irritate or ANNOY someone. The third solution is 'PESTER' which is a six letter word meaning to bother or harass someone persistently. All three words are used to describe the same action of causing someone distress or annoyance.