

包丁がにぶいと、野菜がうまく切れません。
このナイフ、ちょっとにぶくない?
長く使ったので、包丁がにぶくなりました。
"にぶい(鈍い)" is in the lesson "Cooking 1" (Level 18), along with 9 other useful words. LinDuo has 180 topic lessons like this one, 2,379 words in total. Every word has an illustration, a transcription and pronunciation in a female and a male voice. Just 10–15 minutes a day is enough to learn them all. Free, and works offline.