寶刀〔宝-〕 bou² dou¹ {bǎo dāo}

noun; a treasured sword (antique)

寶刀不老〔宝---〕 bou² dou¹ bat¹ lou⁵ {bǎo dāo bù lǎo}

1. lit. a good sword always remains sharp (idiom)
2. fig. (of one's skills etc) to be as good as ever
3. the old man still has it

寶刀未老〔宝---〕 bou² dou¹ mei⁶ lou⁵ {bǎo dāo wèi lǎo}

treasure knife does not age (idiom); old but still vigorous