cannot

Etymology

can + not

verb

1. Can not (be unable to).
   I cannot open the window. It is stuck.
2. Be forbidden or not permitted to
   The Pupil after his Pupillarity, had granted a Diſcharge to one of the Co-tutors, which did extinguiſh the whole Debt of that Co-tutor, and conſequently of all the reſt, they being all correi debendi, lyable by one individual Obligation, which cannot be Diſcharged as to one, and ſtand as to all the reſt. 1668 December 19, James Dalrymple, “Mr. Alexander Seaton contra Menzies” in The Deciſions of the Lords of Council & Seſſion I (Edinburgh, 1683), page 575
   The US supreme court has ruled unanimously that natural human genes cannot be patented, a decision that scientists and civil rights campaigners said removed a major barrier to patient care and medical innovation. 2013-06-21, Karen McVeigh, “US rules human genes can't be patented”, in The Guardian Weekly, volume 189, number 2, page 10
   You cannot enter the hall without a ticket.

noun

1. Something that cannot be done.
   the cans and cannots
2. A person who cannot do (something).