multee kertever

"multee kertever" is an old or dialect word meaning very bad. If your teen uses it, they have most likely picked it up from a book, video game, period drama, or a regional grandparent rather than a modern peer group. There is no cause for concern here; the word is largely out of contemporary teen usage. If it appears in a school text, it is being studied for vocabulary or historical context. You can treat it like any other archaic vocabulary item.

"multee kertever" is obsolete or literary English meaning very bad. It is mainly heard in British English (and Irish English). A more formal or neutral equivalent would be something like "very bad" expressed in standard vocabulary. A common mistake is to use "multee kertever" in modern conversation; it will sound strange or theatrical. Recognise it in older texts, but use the modern equivalent when speaking. If you are a B2 or C1 learner, it is useful to recognise this word when you hear or read it, but think carefully about whether the situation really calls for it before using it yourself.