set off (third-person singular simple present sets off, present participle setting off, simple past and past participle set off)

1. (idiomatic, intransitive) To leave; to set out; to begin a journey or trip.

   He set off in search of better opportunities.

2. (idiomatic, transitive) To begin; to cause; to initiate.

   Coordinate term: kick off

   I had no idea that one simple comment would set off such a huge argument.

3. (idiomatic, transitive) To cause to explode, let off.

   What a tragedy, that someone would set off a bomb in a crowded place.

4. (idiomatic, transitive) To put into an angry mood; to start (a person) ranting or sulking, etc.

   Don't set him off or he won't shut up all day.

5. (idiomatic, transitive) To enhance by emphasizing differences.

   Her plain white dress was set off by a bright red stole.

   • 1902, John Buchan, The Outgoing of the Tide:

     And then one afternoon in the hinder end of April came young Heriotside riding to the Skerburnfoot. His arm was healed, he had got him a fine new suit of green, and his horse was a mettle beast that well set off his figure.

6. (idiomatic, transitive) To offset, to compensate for: to reduce the effect of, by having a contrary effect.

   My taxes did not increase because the amount of my raise was set off by my losses in the stock market.

   • 1908, Henry James, chapter XXXIX, in The Portrait of a Lady (The Novels and Tales of Henry James), New York edition, volume (please specify |volume=I or II), Boston, Mass., New York, N.Y.: Charles Scribner's Sons, →OCLC ↗; republished as The Portrait of a Lady (EBook #283), United States: Project Gutenberg, 1 September 2001:

     When a woman had made such a mistake, there was only one way to repair it,—to accept it. One folly was enough, especially it was to last for ever; a second one would not much set it off.

7. (printing, historical) To deface or soil the next sheet; said of the ink on a freshly printed sheet, when another sheet comes in contact with it before it has had time to dry.

• German: losmachen (coll.), abgehen, sich absetzen, losziehen (person)
• Russian: отправляться
• Spanish: partir

• German: auslösen, entfesseln (exalted), in Gang bringen / setzen
• Italian: causare, determinare

• German: zünden, abbrennen
• Italian: innescare

• French: mettre en colère
• German: anzünden (informal), aufbringen (gegen)

• German: absetzen, hervorheben