monster

The word 'monster' originates from the Latin monstrum, which referred to a divine portent or omen, often one that was unnatural and terrifying. This, in turn, derives from the verb monere, meaning "to warn," as such phenomena were seen as warnings from the gods. Over time, the meaning shifted from the sign of a prodigy to the prodigious and abnormal thing itself—a creature that defies the natural order. By the late 14th century, it entered English with its core modern sense of an imaginary, frightening creature, later extending metaphorically to cruel people or things of enormous size.

Structure: monstr (to show, to warn) + er (agent suffix) 'monstr' is from Latin monstrum, meaning "divine omen, portent, monster," from the verb monere, "to warn, advise." The '-er' is an English agent suffix indicating "one who or that which does something."