The term 'SPRING FOR LUNCH' can be summarized as a TREAT for lunch. The crossword solution for this term is TREAT, which is a five-letter word. A TREAT for lunch could be something special like a picnic in the park or a surprise meal from a favorite restaurant. It could also be something small like a special dessert or a surprise snack. Whatever it is, it's a nice way to enjoy a meal and show someone that you care.