Activity means the state of being in motion, or the expenditure of energy. Activity is a broad word, applicable to physical or mental exertions or pursuits by a person or a group, and is often used to convey the idea of a number of separate simultaneous or successive operations: the activity of the heart; a busy week filled with social activities .

Bustle , commotion , stir and to-do all mean a feverish, noisy or excited activity by either an individual or a group. Bustle suggests busyness, activity with a purpose: the bustle on the floor of the Stock Exchange. Commotion suggests excitement and noisy disorganization: the commotion in a schoolroom during the teacher’s absence. Stir suggests excited movement or discussion: the stir aroused in the audience by the speaker’s remarks. To-do hints at unnecessary or uncalled-for excitement: the to-do generated by the new secretary coming to work in slacks and flatties.