# bad /ˈbæd/ (US) · /bˈæd/ (UK) Source: https://englishreference.com/word/bad Updated: 2026-04-30 ## Senses ### 1. not good / low quality adjective · CEFR A1 not good in quality, or not what you wanted. For teachers: of poor quality, inadequate, or failing to meet a required standard. - The weather was really bad yesterday, so we stayed inside all day. - The company's reputation suffered after a series of bad reviews highlighted the inconsistent quality of their customer service. Usage: Commonly used as a predicative adjective after linking verbs. ### 2. behaving poorly adjective · CEFR A1 used to describe a person or animal that does not follow the rules. For teachers: behaving in a disobedient, mischievous, or socially unacceptable manner. - The teacher told the student that his behavior in class was bad. - The puppy was being bad again, chewing on the expensive leather sofa while its owners were in the other room. Teaching tip: Often used by parents or teachers when speaking to children. ### 3. harmful or unhealthy adjective · CEFR A2 something that can hurt your health or cause problems. For teachers: having a deleterious effect on health, well-being, or safety. - Eating too much sugar is bad for your teeth. - Prolonged exposure to blue light from screens late at night is considered bad for maintaining a healthy sleep cycle. Usage: Often followed by the preposition 'for'. ### 4. spoiled or rotten adjective · CEFR B1 food that is no longer safe to eat. For teachers: referring to food that has decayed or perished and is no longer fit for consumption. - Don't drink that milk; it smells like it has gone bad. - The entire shipment of produce went bad because the refrigeration system failed during the long journey across the border. Usage: Commonly used with the verb 'go' (e.g., 'the milk went bad'). ### 5. excellent or cool adjective · CEFR C1 · Slang very good, stylish, or impressive. For teachers: denoting excellence, stylishness, or impressive toughness; a case of semantic inversion. - That new car he bought is so bad. - In the eighties, 'bad' became a popular slang term to describe something that was actually incredibly impressive or fashionable. Teaching tip: This is a classic example of 'reclaimed' or 'inverted' slang where a negative word is used positively. ### 6. a mistake noun · CEFR B1 · Informal a way to say you made a mistake. For teachers: an admission of a mistake or fault, typically used in the phrase 'my bad'. - I forgot to bring your book back today—my bad. - When the waiter realized he had brought the wrong order to the table, he simply shrugged and said, 'My bad.' Usage: Almost exclusively used in the fixed expression 'my bad'. Teaching tip: Tell students this is a very casual way to apologize for small errors, but not for serious offenses. ### 7. unwanted goods noun · CEFR C2 · Technical something that people do not want and would pay to get rid of. For teachers: an item or service that has negative utility to the consumer. - Pollution is an example of an economic bad. - Economists distinguish between 'goods' that increase utility and 'bads', such as household waste or industrial pollution, which individuals pay to avoid. Usage: Used as a countable or uncountable noun in economic theory. Teaching tip: This is a highly specialized term; students will likely only see it in academic economic texts. ### 8. very much adverb · CEFR B2 · Informal · American English very much or very strongly. For teachers: used as an intensifier to mean 'to a great degree' or 'badly'. - I want to go on vacation so bad. - After working twelve hours straight without a break, he needed a glass of water really bad. Usage: Usually follows verbs like 'want' or 'need'. Teaching tip: In formal writing, students should use 'badly' instead of 'bad' as an adverb. --- From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.