PLUMB

n., adv., adj., & v. --n. a ball of lead or other heavy material, esp. one attached to the end of a line for finding the depth of water or determining the vertical on an upright surface. --adv. 1 exactly (plumb in the centre). 2 vertically. 3 US sl. quite, utterly (plumb crazy). --adj. 1 vertical. 2 downright, sheer (plumb nonsense). 3 Cricket (of the wicket) level, true. --v.tr. 1 a measure the depth of (water) with a plumb. b determine (a depth). 2 test (an upright surface) to determine the vertical. 3 reach or experience in extremes (plumb the depths of fear). 4 learn in detail the facts about (a matter). øout of plumb not vertical. plumb-line a line with a plumb attached. plumb-rule a mason's plumb-line attached to a board. [ME, prob. ult. f. L plumbum lead, assim. to OF plomb lead]