laugh

v. make a sound which expresses amusement (or scorn, etc.); ridicule, make fun of

n. act of laughing; sound which expresses amusement (or scorn, etc.); something which amuses or causes laughter

Laughter is an audible expression or appearance of merriment or amusement or an inward feeling of joy and pleasure(laughing on the inside). It may ensue (as a physiological reaction) from jokes, tickling and other stimuli. Inhaling nitrous oxide can also induce laughter; other drugs, such as cannabis, can also induce episodes of strong laughter. Strong laughter can sometimes bring an onset of tears or even moderate muscular pain as a physical response to the act. Laughter can also be a response to physical touch, such as tickling, or even to moderate pain such as pressure on the ulnar nerve ("funny bone").
See more at Wikipedia.org...

Noun
1. the sound of laughing
(synonym) laughter
(hypernym) utterance, vocalization
(hyponym) cachinnation
(derivation) express joy, express mirth
2. a facial expression characteristic of a person laughing; "his face wrinkled in a silent laugh of derision"
(hypernym) facial expression, facial gesture
(derivation) express joy, express mirth
3. a humorous anecdote or remark intended to provoke laughter; "he told a very funny joke"; "he knows a million gags"; "thanks for the laugh"; "he laughed unpleasantly at hisown jest"; "even a schoolboy's jape is supposed to have some ascertainable point"
(synonym) joke, gag, jest, jape
(hypernym) wit, humor, humour, witticism, wittiness
(hyponym) belly laugh, sidesplitter, howler, thigh-slapper, scream, wow, riot
(part-meronym) punch line, laugh line, gag line, tag line
(derivation) express joy, express mirth
Verb
1. produce laughter
(synonym) express joy, express mirth
(antonym) cry, weep
(hypernym) express emotion, express feelings
(hyponym) bray
(see-also) laugh off, laugh away
(derivation) joke, gag, jest, jape

(v. t.)
To express by, or utter with, laughter; -- with out.
  

(v. t.)
To affect or influence by means of laughter or ridicule.
  

(v. i.)
To show mirth, satisfaction, or derision, by peculiar movement of the muscles of the face, particularly of the mouth, causing a lighting up of the face and eyes, and usually accompanied by the emission of explosive or chuckling sounds from the chest and throat; to indulge in laughter.
  

(v. i.)
Fig.: To be or appear gay, cheerful, pleasant, mirthful, lively, or brilliant; to sparkle; to sport.
  

(n.)
An expression of mirth peculiar to the human species; the sound heard in laughing; laughter. See Laugh, v. i.
  

wu3 shi2 bu4 xiao4 bai3 bu4
One that retreats fifty steps laughs at one who does a hundred.
This expression refers to two persons who have both made mistakes, though the mistakes of one may be less serious than the other's. The pot calls the kettle black.