plumb the depths, to

plumb the depths

1. If someone's behaviour plumbs the depths, it is extremely bad. This crime plumbs the very depths of the abyss into which it is possible for the human spirit to sink.
2. If you plumb the depths of something, you find out everything you can about it. He doesn't plumb the depths of a text in the way of his contemporaries. We can never fully plumb the depths of the unconscious.
3. If someone plumbs the depths of an unpleasant or difficult situation or emotion, they experience it to an extreme degree. They frequently plumb the depths of loneliness, humiliation and despair. Note: The above expressions relate to sailing in former times. When a ship was in shallow water one of the sailors would find out how deep the water was by dropping a piece of lead on a string, called a `plumb', over the side of the ship.
See also: depth, plumb

plumb the depths

1 reach the extremes of evil or unhappiness. 2 inquire into the most obscure or secret aspects of something.
See also: depth, plumb

plumb the depths, to

Get to the bottom of something. This term has been used literally since the first half of the 1500s for measuring the depth of a body of water, using a line weighted with a lead ball, or plumb. Its figurative use came a few decades later and has survived the death of the literal meaning, which gave way to more sophisticated means of measuring. E. W. Gregory used it in The Furniture Collector (1916): “. . . engaged in trying to plumb the depths of duplicity to which dealers can descend in faking old furniture.”
See also: plumb