cannot

Cannot is the negation of the auxiliary verb can, used to express inability, lack of permission, or logical impossibility. It appears in sentences such as “I cannot swim” (inability) and “You cannot enter without a ticket” (prohibition). In conditional or hypothetical contexts, cannot can convey that a certain outcome is not possible under given circumstances.

Usage and form: The standard spelling in modern English is cannot, written as a single word. The contracted form can’t is common in informal writing and speech. The two-word form can not is rare and typically reserved for special constructions, such as when not modifies a following element, or in the expression not only … but also, where you may encounter phrases like “She can not only sing but also dance.”

Etymology and history: Cannot derives from can + not, a combination found in Middle English and preserved in contemporary English as the primary negated form of can. The contracted version can’t developed later and remains widespread in everyday language, especially in spoken form, while cannot maintains a more formal tone suitable for writing.

Variants and nuance: Cannot can express inability, prohibition, or impossibility, as in “I cannot attend the meeting” or “You cannot legally claim that.” The phrase cannot but is a literary construction meaning “cannot help but” or “must,” as in “We cannot but agree with the conclusion.” The word is sometimes confused with can not in older texts or in specific emphatic constructions, but the modern norm favors cannot for most purposes.