plumb

the metal bob of a plumb line

measure the depth of something

weight with lead

examine thoroughly and in great depth

adjust with a plumb line so as to make vertical

exactly vertical; "the tower of Pisa is far out of plumb"

completely; used as intensifiers; "clean forgot the appointment"; "I'm plumb (or plum) tuckered out"

conforming to the direction of a plumb line

exactly; "fell plumb in the middle of the puddle"