/ plʌm; NAmE / verb , adverb
■ verb
[ vn ] ( literary ) to try to understand or succeed in understanding sth mysterious
SYN fathom :
She spent her life plumbing the mysteries of the human psyche.
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IDIOMS
- plumb the depths of sth
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PHRASAL VERBS
- plumb sth in
■ adverb
1.
(used before prepositions) exactly :
He was standing plumb in the middle of the road.
2.
( old-fashioned , NAmE , informal ) completely :
He's plumb crazy.
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WORD ORIGIN
verb and adverb Middle English (originally in the sense sounding lead ): via Old French from Latin plumbum lead.
pvsym. late 19th cent. (in the sense work as a plumber ): back-formation from plumber .