The crossword solution for the term 'Johnny with a guitar' is CASH, which is a four-letter word. Johnny CASH was an American singer-songwriter, guitarist, actor, and author who was widely considered one of the most influential musicians of the 20th century. He is known for his deep, distinctive voice, his signature look, and his many hit songs such as 'Folsom Prison Blues' and 'Ring of Fire'. He was also known for playing the guitar, making him an iconic figure in the music industry.