bogeyman

As a noun bogeyman

is a menacing, ghost-like monster in children's stories.

As an adjective undefined is

lacking a definition or value.

As nouns the difference between bogeymen and bogeyman

is that bogeymen is while bogeyman is a menacing, ghost-like monster in children's stories.

As nouns the difference between taxonomy and bogeyman

is that taxonomy is the science or the technique used to make a classification while bogeyman is a menacing, ghost-like monster in children's stories.

As nouns the difference between bogeyman and bogeywoman

is that bogeyman is a menacing, ghost-like monster in children's stories while bogeywoman is a female bogeyman.

Whangdoodle is a synonym of bogeyman.

As nouns the difference between bogeyman and whangdoodle

is that bogeyman is a menacing, ghost-like monster in children's stories while whangdoodle is a whimsical monster in folklore and children's fiction; a bugbear.