Admonition and premonition are two members of a small word family based on a root pertaining to scolding or warning. The family is introduced below.
The Latin verb monere, meaning “advise,” “express disapproval,” or “warn,” is the root of admonition and premonition. Admonition and its sister noun admonishment are distinguished by the senses “warning about behavior” and “criticism of behavior,” respectively; the verb form, admonish, applies to both senses. A premonition, meanwhile, is a feeling of forewarning not based on conscious thought; unlike admonition, the noun does not take other forms. Monition itself, meanwhile, is a rare noun meaning “caution” or “warning.”
Summon is also descended from monere, originally in the form of the Latin verb summonere, which means “warn secretly” (the first syllable is a variant of sub-); the English verb means “send for,” with the connotation of an imperative; to summon up is to call forth or evoke, as in the notion of summoning up courage or another emotion. Something that can be summoned is summonable, and one who summons is a summoner. Summons is a noun meaning “an act of summoning,” usually in the form of an order to appear in court; the plural is summonses.
Other words based on monere include monitor, which originally referred to one who admonishes, checks, or reminds and came to mean “guide,” “instructor,” and “overseer.” This word has several other distinct senses: First, the monitor lizards, a genus that includes the Komodo dragon, were supposedly named for a habit some species have of standing on two legs or acting otherwise to check on or warn about the presence of predators. Second, a Civil War–era warship armored with iron was dubbed the Monitor with the notion that it would admonish its foes; the name was applied to similar and not-so-similar vessels for the next hundred years. Finally, the use of the word to describe equipment for checking the quality of electronic transmissions led to its employment in reference to display screens for televisions, computers, and other devices.
Then there’s monument, from the sense of monere pertaining to reminding: A monument is a written document, record, or tribute; a structure honoring a person or event or something pertaining to a notable person or thing; or a boundary marker. A national monument is one of a class of places set aside by a country for its historic, scenic, or scientific significance. Because of the associations of structural monuments with grandeur, something great or outstanding is said to be monumental; monumentally is the adverbial form.
Finally, monster derives from a sense of “something that warns”: The word describes an abnormal, strange, or terrifying living thing; something cruel, threatening, or ugly; or something especially large or successful. Monster is employed as an adjective as well in the last sense, while monstrous applies for the other meanings and monstrously serves as an adverb.