<p><strong>Noun</strong></p><ul><li>a small mass of lead or other heavy material, as that suspended by a line and used to measure the depth of water or to ascertain a vertical line.</li><li>expiration of breath.</li><li>an end or termination, as of life or a contract.</li></ul><p><strong>Adjective</strong></p><ul><li>true according to a plumb line perpendicular.</li><li>Informal. downright or absolute.</li></ul><p><strong>Adverb</strong></p><ul><li>in a perpendicular or vertical direction.</li><li>exactly, precisely, or directly.</li><li>Informal. completely or absolutely: She was plumb mad. You're plumb right.</li></ul><p><strong>Verb</strong></p><ul><li>(used with object) to test or adjust by a plumb line.</li><li>to make vertical.</li><li>to sound with or as with a plumb line.</li><li>to measure (depth) by sounding.</li><li>to examine closely in order to discover or understand: to plumb someone's thoughts.</li><li>to seal with lead.</li><li>to weight with lead.</li><li>to provide (a house, building, apartment, etc.) with plumbing.</li><li>(used without object) to work as a plumber.</li></ul>