Verb

To knock against or run into with a jolt.

To move up or down by a step.

I bumped the font size up to make my document easier to read.

(Internet) To post in an Internet forum thread in order to raise the thread's profile by returning it to the top of the list of active threads.

(chemistry, of a superheated liquid) To suddenly boil, causing movement of the vessel and loss of liquid.

* 1916 , Albert Prescott Mathews, Physiological chemistry

Heat until the liquid bumps , then reduce the heat and continue the boiling for 1½ hours.

To move (a booked passenger) to a later flight because of earlier delays or cancellations.

* 2005 , Lois Jones, EasyJet: the story of Britain's biggest low-cost airline (page 192)

Easyjet said the compensation package for passengers bumped off flights was 'probably the most flawed piece of European legislation in recent years'...

To move the time of a scheduled event.

* 2010 , Nancy Conner, Matthew MacDonald, Office 2010: The Missing Manual , p. 332:

A colleague emails with news that her 4:30 meeting got bumped to 3:30.

(archaic) To make a loud, heavy, or hollow noise; to boom.

* Dryden

as a bittern bumps within a reed

Verb

(ergative) To cause (something) to move rapidly in opposite directions alternatingly.

* {{quote-book, year=1963, author=(Margery Allingham), title=(The China Governess)

, chapter=19 citation , passage=Meanwhile Nanny Broome was recovering from her initial panic and seemed anxious to make up for any kudos she might have lost, by exerting her personality to the utmost. She took the policeman's helmet and placed it on a chair, and unfolded his tunic to shake it and fold it up again for him.}}

To move (one's head) from side to side, especially to indicate a negative.

To move or remove by agitating; to throw off by a jolting or vibrating motion.

* (William Shakespeare) (1564-1616)

Shake off the golden slumber of repose.

* (John Bunyan) (1628-1688)

I could scarcely shake him out of my company.

To disturb emotionally; to shock.

* {{quote-magazine, date=2013-07-20, volume=408, issue=8845, magazine=(The Economist)

, title= The attack of the MOOCs , passage=Since the launch early last year of […] two Silicon Valley start-ups offering free education through MOOCs, massive open online courses, the ivory towers of academia have been shaken to their foundations. University brands built in some cases over centuries have been forced to contemplate the possibility that information technology will rapidly make their existing business model obsolete.}}

To lose, evade, or get rid of (something).

To move from side to side.

*, chapter=23

, title= The Mirror and the Lamp , passage=The slightest effort made the patient cough. He would stand leaning on a stick and holding a hand to his side, and when the paroxysm had passed it left him shaking .}}

To shake hands.

To dance.

To give a tremulous tone to; to trill.