Someone who guards, watches over, or protects. / (law) A person legally responsible for a minor (in loco parentis). / (law) A person legally responsible for an incompetent person.

The act or process of guiding. / Advice or counselling on some topic. / Any process or system to control the path of a vehicle, missile etc.

A non-specific rule or principle that provides direction to action or behaviour. / A plan or explanation to guide one in setting standards or determining a course of action.

(idiomatic, cricket) (For a new batsman, with help from the umpire) to mark a point on the popping crease in front of his wicket so that he knows where it is behind him; to guard.

A group or association mainly of tradespeople made up of merchants, craftspeople, or artisans for mutual aid, particularly in the Middle Ages. / A corporation.

A thin loop surrounding the trigger of a weapon to keep it from accidental discharge.

(historical, also figuratively) A machine used for the application of capital punishment by decapitation, consisting of a tall upright frame from which is suspended a heavy diagonal-edged blade which is dropped on to the neck of the person to be executed; also, execution using this machine.

(law, politics, informal); (also figuratively) To execute (someone) with a guillotine. / To cut or trim (a body part, a stack of paper, etc.) with a guillotine.

Alternative spelling of second-guess

(idiomatic) to vet or evaluate; to criticize or correct, often by hindsight, by presuming to have a better idea, method, etc. / To anticipate or predict someone's actions or thoughts by guesswork.