The term 'requiring great strength or effort' can be summarized by the word 'HERCULEAN', which is a nine-letter word. The term is derived from the Greek mythological figure Hercules, who was known for his extraordinary strength and courage. Hercules was tasked with completing twelve labors, which were incredibly difficult tasks that required immense strength and effort. Thus, the term 'HERCULEAN' has come to mean any task that requires great strength or effort.