(not) at all (with negative verb) / (colloquial) totally, completely (with affirmative verb)

not at all (with negative verb); totally (with affirmative verb)

understanding (of feelings, opinions, circumstances, etc.)

Contraction of わからない (wakaranai), the informal present negative form of わかる (wakaru).

causative of わかる (wakaru) / (fiction, pornography, vulgar) to "teach someone a lesson" via rough rape

polite negative of わかる (wakaru); negative of わかります (wakarimasu)

(humorous) Alternative form of わかりません (wakarimasen, “I don't know”)

mathematics (field of study)

question, problem on homework etc. / a question; a matter (of time etc.) / a problem (something that needs to be dealt with); a trouble / an issue; a matter

You'll be convinced if you listen to me.