The term JOINS ON THE SLY is a crossword solution that is made up of two words, 'joins' and 'on the sly'. The word 'joins' means to come together or unite, while 'on the sly' means to do something secretly or without anyone knowing. Therefore, the phrase JOINS ON THE SLY can be interpreted as two people coming together in secret. This could refer to a romantic relationship, such as eloping, which is defined as running away secretly to get married.