Of a land, suitable or allowable for constructing a building on.
Of a building or other thing, capable of being constructed.
That can be constructed in a plane using only a pair of compasses and a straightedge.
Such that the line segment joining it to the origin can be constructed using only a pair of compasses and a straightedge.
Resilient.
Difficult or impossible to break and therefore able to withstand rough usage.
Not able to be broken in.
Something that cannot be broken.