

一人で晩ご飯を食べるのは寂しいです。
家族に会えなくて寂しい?
友だちが国に帰って、寂しいです。
"さみしい(寂しい)" is in the lesson "Adjectives 4" (Level 17), along with 11 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.