entraver

Two very different senses: literally to hinder, obstruct, or get in the way of something (entraver la circulation, entraver une enquête), and, in slang, to understand (t'entraves rien ?). The slang sense is common in casual speech and rap.

• Les travaux entravent la circulation en centre-ville. — The roadwork is obstructing traffic downtown.
• Cette clause entrave la liberté des parties. — This clause restricts the parties' freedom.
• J'entrave rien à ce qu'il raconte. — I don't understand a thing he's saying.

Learners who only know the formal "hinder/obstruct" sense are often thrown by the completely unrelated slang meaning "to understand" — the two senses belong to different registers and shouldn't be mixed in formal writing.

• expression "J'entrave que dalle" — Common French slang phrase meaning "I don't understand a thing," combining the slang sense of entraver (to understand) with que dalle (nothing) — well documented in French slang dictionaries.