feasible
Possible to do with the time, money, and tools available.
Feasible means possible to do or accomplish with the resources and circumstances you have. When something is feasible, you can actually do it if you put in the work and have what you need.
Imagine your class wants to raise money for new playground equipment. Raising $50 might be feasible with a bake sale. Raising $500 might be feasible with several fundraisers over a few months. But raising $50,000 probably isn't feasible for a classroom, no matter how hard you try. The difference isn't about effort or desire: it's about what's realistically possible given your time, money, and resources.
Engineers and architects constantly ask whether their plans are feasible. Can this bridge actually be built with available materials? Is there enough time to finish the project by the deadline? Scientists designing experiments check whether their research is feasible with their equipment and budget.
The opposite of feasible is infeasible: completely impractical or impossible under current conditions. A feasibility study examines whether a project can actually work before anyone commits serious time or money to it. When adults say something “isn't feasible,” they mean the obstacles are too big or the resources are too limited, even if the goal itself sounds good.