The term 'Grumpy Sort' is a type of sorting algorithm which is based on the idea of repeatedly swapping adjacent elements if they are not in the correct order. The crossword solution for this term is 'CRAB', which is an acronym for 'Compare and Reverse All Blocks'. This algorithm works by comparing two adjacent elements and reversing them if they are not in the correct order. It is a relatively simple algorithm, but it can be quite slow when dealing with large datasets.