perpendicular vs plumb bob

perpendicular and plumb bob both are nouns.

Word	Noun	Adjective	Verb	Adverb
perpendicular	Yes	Yes	No	No
plumb bob	Yes	No	No	No

perpendicular (noun)	plumb bob (noun)
an extremely steep face	the metal bob of a plumb line
a cord from which a metal weight is suspended pointing directly to the earth's center of gravity; used to determine the vertical from a given point
a Gothic style in 14th and 15th century England; characterized by vertical lines and a four-centered (Tudor) arch and fan vaulting
a straight line at right angles to another line

perpendicular (adjective)	plumb bob (adjective)
intersecting at or forming right angles
at right angles to the plane of the horizon or a base line
so steep as to be nearly vertical