堅物 かたぶつ
katabutsu

Noun

1. straight-laced person; stubborn person

かれ堅物 かたぶつだから、どうも息子 むすこ転職 てんしょくするのにいい かおをしないんだよね。
karewa katabutsudakara dōmo musukoga tenshoku suru noni ii kaō shinai ndayone.
He's a really straight-laced guy, so he doesn't like the idea of his son changing jobs.