| Term | Definition |
| jejune | (adj) 1. without interest or significance; dull; insipid. 2. juvenile; immature; childish. 3. lacking knowledge or experience; uninformed 4. deficient or lacking in nutritive value. |
| jeremiad | (noun) a prolonged lamentation or mournful complaint. |
| jingo | (noun) 1. a person who professes his or her patriotism loudly and excessively, favoring vigilant preparedness for war and an aggressive foreign policy; bellicose chauvinist. 2. English History. a Conservative supporter of Disraeli's policy in the Near East during the period 1877–78. (adj) 3. of jingoes. 4. characterized by jingoism. (Idiom) 5. by jingo! |
| juxtaposition | (noun) 1. an act or instance of placing close together or side by side, esp. for comparison or contrast. 2. the state of being close together or side by side. |
| kowtow | (verb) 1. to act in an obsequious manner; show servile deference. 2. to touch the forehead to the ground while kneeling, as an act of worship, reverence, apology, etc., esp. in former Chinese custom. (noun) 3. the act of kowtowing. |
| koan | (noun) a nonsensical or paradoxical question to a student for which an answer is demanded, the stress of meditation on the question often being illuminating. |
| lachrymose | (adj) 1. suggestive of or tending to cause tears; mournful. 2. given to shedding tears readily; tearful. |
| laconic | (adj) using few words; expressing much in few words; concise. |
| laissez faire | (noun) 1. an economic doctrine that opposes governmental regulation of or interference in commerce beyond the minimum necessary for a free-enterprise system to operate according to its own economic laws. 2. noninterference in the affairs of others. |
| lexicon | (noun) 1. a wordbook or dictionary, esp. of Greek, Latin, or Hebrew. 2. the vocabulary of a particular language, field, social class, person, etc. 3. inventory or record. 4. Linguistics. a. the total inventory of morphemes in a given language. b. the inventory of base morphemes plus their combinations with derivational morphemes. |
| loquacious | (adj) 1. talking or tending to talk much or freely; talkative; chattering; babbling; garrulous. 2. characterized by excessive talk; wordy. |
| lucubrate | (verb) 1. to work, write, or study laboriously, esp. at night. 2. to write learnedly. |
| lugubrious | (adj) mournful, dismal, or gloomy, esp. in an affected, exaggerated, or unrelieved manner. |