- not sounded, measured, or explored with or as with a plumb
- not fully plumbed, or understood
- Not equipped with or connected to a plumbing system.
- Not measured or sounded with a plumb: unplumbed ocean depths.
- Not fully examined or explored: unplumbed ideas.
(comparative more unplumbed, superlative most unplumbed)
- Not measured for depth, as if with a plumb.
- The unplumbed depths of the sea will remain a mystery to land-bound humans.