These words refer to the act of bringing something to an end, or a complete rest. Stop in its generality has few specific implications, being open to any colouration that context gives it: stopping her gently in mid-sentence with a single brush of his hand; They stopped the charging elephant dead in his tracks with a barrage of bullets.

Arrest , check and block suggest a stopping of motion or activity by the application of a countering force: words that arrested his flight in mid-career across the room. All three words can suggest an interruption or prevention of activity that might well begin again once the countering force is removed.

• The child’s development was arrested by an over-permissive regimen; therapy to check the course of the disease, although they could not cure it; blocking the enemy’s access to the sea.

Arrest most specifically suggests the freezing of something just as it was at the time activity stopped. Check suggests keeping something hemmed in so that it cannot continue. Block suggests the interposition of an obstacle that cannot be got around.

Discontinue relates particularly to a manufactured item that is gradually phased out of production: a notice that they were discontinuing several lines of spare parts previously listed in their catalogue. It may refer also to the gradual abandonment of a habitual way of doing things or of some activity in which one has been engaged: The practice of binding the feet of Chinese women was finally discontinued ; he discontinued two of his university courses. In other uses, it may seem a rather longwinded way to say stop .

Cease most often suggests an abrupt stopping : The officer ordered him to cease his whistling immediately. Halt also suggests suddenness, but it may suggest as well a stopping of motion brought about by authority or force: brusquely halting her at the gate with a demand to see her papers. Prevent can apply to anything that results in stopping or forestalling an action by whatever means. The action, in this case, may be blocked before it has been set in motion: a thorough grounding in fundamentals to prevent reading difficulties from occurring later on; a programme to prevent drug addiction rather than treat it once it has a hold on its victims. The word can apply also to a countering force, but only the potential or psychological effectiveness of such a force may be indicated: maintaining troop readiness to prevent being overwhelmed by surprise attack; a puritanical streak that prevented her from completely surrendering herself to any momentary pleasure.

These words refer to the act of coming to rest or of breaking off previous activity. Stop is the most general, least formal and most commonly used, yielding the fewest specific suggestions about the way in which activity is concluded: a clock that stopped and started erratically; listening with a stethoscope to find out if the old man’s heart had stopped ; where the bitumen stops and a dirt track takes over. Cease carries the specific implication of a total extinction: a newspaper that has ceased publication. It may sometimes suggest abruptness: As suddenly as it began, the rain ceased .

Halt is similar to cease but has specific reference to the abrupt, decisive termination of movement: halting only at the edge of the cliff; demonstrators who marched as a body into the square, halted in its centre, and then threw themselves down on the pavement. Quit may also indicate an arbitrary halting, but this is usually voluntary or agreed upon: They worked until 5.00 P.M. and then quit . Knock off is more frequently used and more informal than quit in the sense of stopping work: We knock off at 12.30 for lunch. Most often applying to work or effort, quit can sometimes suggest disgruntlement or defeat: an official who quit his job in protest at government policy; Battered as he was in the fight, he refused to quit . It may also suggest cessation because of enfeeblement or lack of energy: The motor coughed and sputtered, turned over a few times, and then quit on us. Desist is the most formal word here. It is applied to an active agency and implies forbearance. Specifically, it presupposes the existence of opposition or resistance to continuance, or the presence of obstacles that seem insurmountable: finally desisting in his fruitless efforts to find the missing heir. It is often coupled with cease in legal parlance: ordered to cease and desist from false advertising.