I know from general knowledge that לֵיצָנוּת is forbidden. It is generally translated as being cynical, scoffing or mocking. I have also seen discussion in various mussar and hashkafic works but I would love to see some more halachic sources on this.
Are there any halachic sources that deal with לֵיצָנוּת, so that we can have a good definition and set of principles by which we can positively identify examples of לֵיצָנוּת when we see/make them?
By examples, I mean laws of speech. Yes, לֵיצָנוּת is a middah, but the way we know someone is a לֵיצָן is by what he says. There are certain things you are not allowed to think or say, because they are לֵיצָנוּת, but there doesn't seem to be any rigorous dealing with the subject, similar to the Laws of Lashon Hara, for example. Shmuel has brought strong sources that "clowning around" also counts, so perhaps there are laws of behaviour as well.
Here are some examples I've heard that I always wondered, does this count as לֵיצָנוּת or not?
- Me: "It's funny that the gematria for Elokim is 86, and bli mah is 87", Him: "you and me clearly have a different sense of humour" [explanation: mockery of gematrias?]
- [Insert group name] do [x, y, z] because they are just trying to get as many adherents to the movement as possible [explanation: cynicism 101]
- Chazal clearly didn't know much science, but it is understandable that they must have learned some things from the greek philosophers [explanation: cynicism?]
- Use of sarcasm when making a point [explanation: ridicule?]
- [Insert group name] love [Insert sefer or Rav's name] more than Tanach/Moshe! [explanation: ridicule?]
- I don't learn X because it's too emotional and I prefer to be intellectual [explanation: thinly veiled scoffing?]
And now a behavioral example:
- A friend of mine was in a yeshiva for more difficult bochurim, the type that are in danger of going off the derech. In that yeshiva, the rebbe would come and take people's blankets if they didn't get up for shacharit. One bochur, in rebellion to this, decided to start sleeping naked. [explanation: clowning around? Would laughing at this story also be forbidden?]
EDIT:
Accepting an answer and awarding the bounty was extremely difficult. People reading this question should be encouraged to read all the answers, as all of them provide essential information towards the question, as well as demonstrate that it can be quite hard to pin down this all-encompassing negative character trait and its foibles.
For a halachic definition, the three closest results we have received, which all agree, are:
- By Dov, awarded bounty for effort in supplying a definition, which is what the bounty was for:
Rav Mordechai Gifter zt"l:
Leitzanus has a connotation of cynicism. It refers to taking everything which is high and knocking it down. A leitz takes everything that is holy and tries to demonstrate the profane side of it.
- By Schmerel, short, simple, sweet and matches what I've heard in various places, a great definition that goes well with Dov's:
The only one to give me a clear answer was Rabbi Forscheimer (the main posuk in Lakewood) He said that it means anything that makes light of a serious or important issue in Yiddishkeit.
- And fulltimekollelguy's answer, accepted because it meets the title of the question best, providing a great source to a halachic work on Leitzanut, covering 50 pages and sounds like it is almost certainly exactly what I am looking for and I will be striving to get hold of:
ג נחלקה הליצנות לארבע חלקים החלק הראשון המתלוצץ בבני אדם ונותן בהם דופי ומבאיש את ריחם בעיני האדם וחלק זה נכלל גם בכת מספרי לשון הרע החלק השני הלועג לבני אדם שמבזה אותם בלבו לקוצר השגתם במעלות או בהצלחות הזמן ובזה מראה בנפשו שמאמין שההצלחה ביד בני אדם החלק השלישי מי שלועג תמיד לדברים ולפעולות ואין דעתו להבזות בעליהם אך מרחיק הדברים שאין להרחיקם ומרחיק תועלת הפעולות שיש תקוה לתועלתן ופעמים שמביאה מדת ליצנות את האדם לידי מינות שמלעיג על המצוות החלק הרביע הקובע עצמו תמיד לשיחה בטלה ודברים בטלים כדרך יושבי קרנות ויש שתי רעות בדבר זה האחד שכל המרבה דברים מביא חטא והשני כי הוא בטל מדברי תורה כי בזמן הזה יוכל להשיג הנעימות לקנות חיי עולם
Other quoted works that seem to define the term are:
Encyclopedia Talmudit (in Yehuda's answer), and Derech Chaim as quoted in Shmuel's answer.
There were many other works quoted, by different people and all of them contribute to the answer I am looking for and I thank everyone who responded with immense gratitude. If I ever write a "Practical Guide" or something on the topic, I will be mentioning everyone!