Capable of being done.
"Running a first marathon on only sixteen weeks' training? Yes, it's do-able. You won't enjoy it, dude, but it's do-able."
mountain biking term describing an up coming obstacle
or difficult section of trail that will be difficult to ride
but not impossible
the trail ahead is really steep and littered with loose rocks but its do-able
also one biker will ask another biker "do-able?"