(euphemistic) A child who is particularly difficult to raise or educate, especially due to a lack of self-control and disruptive and antisocial behavior.

Something easy, not difficult, not posing problems.

certainly, sure (said when granting a request) / no thanks is necessary; you're welcome (said in response to an expression of gratitude)

(law, US): Evidence which a party to a lawsuit does not have to reveal during the discovery process because it represents the thought process of the attorney preparing for trial.

(law enforcement) A deliverer of processes or summonses, the formal announcements of the beginning of a legal action; a huissier de justice or other equivalent position in other legal systems.

(law) the area of law concerned with the ownership and conveyance of property rights and title. / The formal course in property law required of most first-year law school students in common-law systems.

(law) The delivery of information to a person or entity providing notice that they are being sued with sufficient detail for them to respond to the suit.

(set theory) The set of all possible pairs of elements whose components are members of two sets. Notation: X⨯Y=(x,y)|x∈X∧y∈Y.

(arithmetic) The result of multiplying no numbers, conventionally defined to equal one.

(physics, astronomy) the relatively slow nucleosynthesis process, in giant stars, in which neutron capture synthesises elements up to atomic mass number 210 (at which point alpha decay becomes a deterrent to further building).