Other forms: provisorily
Anything that's provisory is dependent on certain conditions. Your provisory agreement to take your sister to the zoo for the day depends on her agreeing to buy you lunch.
When a statement or agreement is described as provisory, that means it has certain qualifications attached to it. In other words, you'll do something, but only if a condition is met. A provisory college acceptance letter might state that it depends on your grades for the final semester of your senior year. The qualification or condition itself is known as a proviso.