真剣
しんけん · shinken · JLPT N3 · na-adj
earnestness
⚔️ 真剣 = real (真) + sword (剣): a real blade, not a practice one
A shinken is literally a live sword, as opposed to a wooden or bamboo training sword. Fighting with a real blade means no playing around, so the word came to mean being in earnest. 真剣に = seriously, for real.
真 — 匕 (spoon) over 目 (eye) over 八 (eight/base)
真 originally depicted a person or vessel used in ritual, conveying the idea of something genuine or true. Over time the form was reanalyzed as components like 匕, 目, and a base, but the core meaning of 'real, true, genuine' has remained stable since early bronze inscriptions.