straight-laced person; stubborn person
Describes someone who is rigidly serious, inflexible, and often overly formal or moralistic. Can be used critically or humorously.
He's so straight-laced that jokes don't get through to him.
That boss is a stubborn stickler and won't bend the rules.
堅物 describes a serious, straight-laced person with no interest in romance, the opposite of the flirtatious プレイボーイ.
Standard kanji spelling.
Compound of 堅 (かた, 'hard, stiff') and 物 (ぶつ, 'person' or 'thing'). The reading ぶつ is a variant of もの used in compounds. The word literally suggests a 'stiff person' and has been used since the Edo period.