(obsolete) A wrought-iron nail heaving a large flat head, and used for fastening clouts to axletrees, plowshares, etc., also for studding timber, and for various purposes.

(Britain) immediately, without delay

(transitive) to attach with nails / (idiomatic, transitive) to make something (e.g. a decision or plan) firm or certain

(idiomatic) To identify something exactly; to arrive at exactly the right answer.

(idiomatic) An event that increases the likelihood of or causes further failure.

Lacking worldly experience, wisdom, or judgement; unsophisticated. / Not having been exposed to something.

A naive person; a greenhorn.

(US, slang, rare) To do something that is impossible or very difficult, with connotations of pointlessness.

(literally) One who habitually bites or chews their fingernails. / (figuratively) A situation which causes anxiety, suspense, nervousness or discomfort.

An invalid scientific philosophy in which any single instance of refuting data is enough to falsify the entire claim.