Common JLPT N3 い- and な-adjectives for describing things with more nuance.

• 確かたしかcertain, sure
• 重要じゅうようimportant, crucial
• 必要ひつようnecessary
• 当然とうぜんnatural, obvious; of course
• 主なおもなmain, principal
• 苦手にがてpoor at, not good at; dislike
• 得意とくいgood at, one’s strong point
• 真剣しんけんserious, earnest
• 正直しょうじきhonest, frank
• 素直すなおobedient, honest, docile
• 派手はでflashy, showy, gaudy
• 地味じみplain, sober, modest
• 詳しいくわしいdetailed; well-informed (about)
• 厳しいきびしいstrict, severe, harsh
• 親しいしたしいclose, intimate, friendly
• 豊かゆたかabundant, rich, plentiful
• 複雑ふくざつcomplicated, complex
• 確実かくじつcertain, reliable, sure